%■  z2 


Bulletin  No.  28— New  Series. 

U.  S.  DEPARTMENT   OF  AGRICUL1  LTRE, 

DIVISION  OJF  ENTOMOLOGY. 


INSECT  ENEMIES  OF  THE  SPRUCE 
IX  THE  NORTHEAST. 


POPULAR  ACCOUNT  OF  RESULTS  OF  SPECIAL  INVESTIGATIONS,  WITH 
RECOMMENDATIONS  FOR  PREVENTING  LOSSES. 


Prepared  Under  the  Direction  op  the  Entomologist 


A.  I).  HOPKINS,  IV.  D.. 
Vice-Director  q  •■■  mia  Agricultural 


WASHINGTON: 

GOV  E  B  N  M  E  N  l      I'  B  I  N  TING     <  »  F  K  I  < '  B  . 


DIVISION  OF  ENTOMOLOdY. 

Entomologist:  L.  O.  Howard. 
First  Assistant  Entomologist:  C.  L.  Marlatt. 

Assistant  Entomologists:  Th.  Pergande.  F.  H.  Chittenden.  Frank  Benton. 
Investigators:  E.  A.  Schwarz.  D.  W.  Coquillett. 

Assistants:  R.  S.  Clifton,  Nathan  Banks,  F.  C.  Pratt,  Aug.  Busck,  Otto  Heide- 
lnann.  A.  N.  <  "audell,  J.  Kotinsky. 
Artist:  Miss  L.  Sullivan. 


Bulletin  No.  28— New  Series. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

DIVISION  OF  ENTOMOLOGY. 


INSECT  ENEMIES  OF  THE  SPRUCE 
IN  THE  NORTHEAST. 


A  POPULAR  ACCOUNT  OF  RESULTS  OF  SPECIAL  INVESTIGATIONS.  WITH 
RECOMMENDATIONS  FOR  PREVENTING  LOSSES. 


Prkparkd  Under  thb  Direction  or  the  Entomologist 


A.  I).  HOPKINS.  Ph.  D.. 

Vice-Director  and  Entomologist  of  thi  West  Virginia  Agricultural 
Experiment  Sot  ion. 


WASHINGTON : 

G  O  V  E  K  M  M  E  N  T    PRINTING     O  F  F  1  C  F 


LETTER  OF  TRANSMITTAL 


U.  S.  Department  of  Agriculture. 

Division  of  Entomology, 

Washington.  D.  C.  July  1.  1901. 
Sir:  I  transmit  herewith  the  manuscript  of  a  report  by  Dr.  A.  D. 
Hopkins,  entomologist  of  the  West  Virginia  Agricultural  Experiment 
Station,  on  a  trip  taken  in  the  summer  of  1900,  under  the  auspices  of 
this  Division,  to  the  spruce-growing  region  in  New  England,  for  the 
purpose  of  investigating  damage  done  by  insects.  The  attention  of 
the  Department  was  called  to  a  serious  trouble  affecting  the  spruce 
trees,  in  March,  1900,  and  Dr.  Hopkins  was  chosen  for  the  investiga- 
tion for  the  reason  that  he  has  studied  forest  insects  for  many  years 
and  is  generally  known  as  the  leading  forest  entomologist  of  the 
country.  His  report  indicates  that  he  was  not  only  able  to  determine 
the  cause  of  the  difficulty,  but  to  suggest  practical  measures  of  relief. 
I  recommend  that  it  be  published  as  Bulletin  No.  2S.  new  series,  of 
the  Division  of  Entomology. 

Respectfully.  L.  O.  Howard, 

Entomologist. 
Hon.  James  Wilson. 

Si  cretary  of  Agriculture. 


PREFACE. 


OBJECTS. 

The  primary  objects  of  the  investigations  were  (1)  to  determine 
the  cause,  or  causes,  of  a  prevailing  unhealthy  condition  of  the  spruce 
in  certain  sections  of  the  forests  of  Maine.  New  Hampshire,  and  Ver- 
mont, and  to  study  the  prevailing  influences  found  to  be  favorable  or 
unfavorable  to  the  continuance  or  spread  of  the  trouble:  and  (2)  to 
determine,  if  possible,  some  practical  method  by  which  the  owners 
of  the  timber  could  prevent  or  mitigate  the  great  losses  of  valuable 
timber  from  this  cane 

It  is  aimed  in  this  report  to  give  a  popular  account  of  the  investi- 
gations and  the  principal  results,  with  recommendations  of  such 
methods  of  prevention  or  control  as  seem  practical. 

The  details  of  a  technical  nature,  relating  to  results  of  more  inter- 
est to  the  entomological  student  or  investigator,  will  be  reserved  for 
a  special  report  on  this  phase  of  the  subject.  It  is  hoped  that  this 
popular  discussion  will  be  of  interest  and  value  to  the  student  and 
investigator  of  economic  forestry  problems,  as  well  as  to  the  practical 
forester  and  lumberman. 

ACKNOWLEDGMENTS. 

Before  proceeding  further  I  wish  to  express  my  acknowledgments 
to  all  those  who  have  in  any  way  given  encouragement  and  assistance 
in  this  work,  among  whom  the  following  deserve  special  mention: 
The  executive  committee  of  the  regents  of  the  AVest  Virginia  Univer- 
sity and  the  director  of  the  experiment  station,  for  the  necessary 
leave  of  absence;  the  Berlin  Mills  Company,  through  its  president, 
Mr.  W.  W.  Brown,  and  vice-president.  H.  J.  Brown,  for  furnishing 
transportation  and  guide  from  Colebrook.  X.  H..  across  the  State  to 
the  steamboat  landing  on  the  Magalloway  River  in  Maine,  and  with 
guides  and  other  facilities  during  my  stay  in  the  spruce  woods  of  the 
Androscoggin  drainage  north  of  the  Rangeley  Lakes;  to  the  Parma- 
cheenee  Club,  through  its  vice-president,  Mr.  Henry  P.  Wells,  and 
manager.  Mr.  J.  A.  Dunning,  for  accommodations  at  Cam})  Caribou 
and  use  of  the  Forks,  Moosebog,  Barkers  Lake,  and  Lower  Black 
camps,  together  with  other  favors  extended;  and  finally  to  Mr.  Austin 
Cary,  who,  as  expert  forester  to  the  Berlin  Mills  Company,  rendered 
miiM  valuable  service  through  his  special  knowledge  of  the  Maine 
woods  and  the  conditions  in  different  sections  most  desirable  to  visit 
for  investigation. 

A.  I).  Hopkins. 


CONTEXTS. 


Page. 

Outline  of  trip.. ._ ...   9 

The  Androscoggin  region  and  its  spruce  forests 11 

Dead  and  dying  spruce . 13 

Some  characteristics  of  the  dying  and  dead  spruce -  —  14 

Causes  of  decay  and  death . . .. 14 

Relation  of  insects  to  the  trouble.  ._ .  15 

The  spruce-destroying  beetle 15 

Description  of  the  destroyer .. 16 

Life  history  of  the  beetle  .   IT 

How  it  passes  the  fall,  winter,  and  spring _ IT 

When  activitjT  commences  in  the  spring IT 

The  summer  period  .   .. ^... 18 

Summary  of  life  history  . .  .  _ 18 

Explanation  of  diagram 19 

Special  features  of  the  beetle's  work 20 

Kind  of  trees  attacked  . .  20 

How  and  when  the  attack  is  made . 20 

Its  work  in  and  beneath  the  bark  ... ... 20 

The  distinctive,  visible  evidences  of  the  spruce  destroyer's  work.  _ 22 

Pitch  tubes. 22 

Appearance  of  the  leaves 22 

Appearance  of  the  twigs 22 

Appearance  of  the  bark  and  wood 32 

Woodpecker  work 23 

A  common  fungus  on  the  bark  of  dead  trees 23 

The  principal  natural  enemies  of  the  spruce-destroying  beetle . .  _ 24 

A  parasitic  enemy 24 

A  predaceous  beetle _' 24 

Birds  as  enemies  of  the  beetle 25 

A  fungous  disease  of  the  beetle.. 26 

Climatic  conditions 26 

The  principal  insect  allies  of  the  spruce  destroyer 26 

The  spruce  Polygraphus 26 

The  spruce  Tetropium 2T 

Other  insects  . ... 2T 

Historical  references 28 

Remedies  and  methods  of  prevention 30 

Review  of  proposed  methods _   30 

Stripping  off  and  burning  the  bark 30 

Destruction  of  dead  trees 31 

Girdling  trees _   ... 31 

Investigation  of  the  girdled- tree  method 31 

Hack-girdled  and  peeled  spruce . 31 

Report  on  girdling  experiments,  by  Mr.  Austin  Cary 32 

Comments  on  Mr.  Gary's  work 40 

Suggestions  and  recommendations 41 

Methods  of  reducing  the  number  of  beetles  42 

Utilization  of  dead  spruce. 45 

Importance  of  harvesting  the  matured  crop  of  spruce 46 

Summary ....   4T 


ILLUSTRATIONS. 


Plates. 

Page. 

Plate  I.— The  spruces  of  Maine  ... : 50 

II. — Dendrocton  ns  piceaperda  Hopk.  .n.sp._- 52 

III.— Galleries  and  mines  of  the  spruce-destroying  beetles 54 

IV. — Galleries  and  mines  of  Dendroctonus  piceaperda  in  spruce.    50 

V. — Old  galleries  of  Dendroctonus  piceaperda  in  spruce. .   ...... 58 

VI. — Spruce  bark  showing  growth  of  fungus,  Polyporus  volvatus  ....  GO 
VII. — Cocoons  of  Bracon  simplex,  a  parasite  of  the  spruce-destroying 

beetle 62 

VIII. — Work  of  secondary  and  other  enemies  of  spruce  .  .  04 

IX.— Galleries  of  Polygraphia  rufipenn  is,  showing  different  stages 00 

X. — Mines  of  Tetropium  cinnamopterum 08 

XI.—  Work  of  Xyloterus  bhrittatus  .  ......     .. 70 

XII. — Work  of  Dendroctonv 8  frontalis  and  Dendrocton  us  terebrans 72 

XIII.— Top  of  Black  Spruce  infested  with  a  caterpillar  and  a  plant-louse.  74 

XIV. — Dead  spruce:  also  fir  and  birch 70 

XV.— Timber  flooded  and  killed  by  water  on  the  Magalloway 78 

XVI.— Sections  of  wood  cut  from  Balsam  Fir  showing  rapid  growth  after 

the  old  spruces  die  or  are  felled 80 

Text  Figures. 

Fi<;.  1. — Diagram  illustrating  the  dormant  and  active  periods  of  develop- 
ment of  Dendroctonus  piceaperda . 19 

2. — Trees  girdled  by  different  methods 82 

8 


INSECT  ENEMIES  OF  THE  SPRUCE  L\  THE 

NORTHEAST. 


OUTLINE  OF  TRIP. 

(  Mi  May  22.  1900,  I  arrived  at  Brunswick^  Me.,  where  I  learned  that 
Mr.  Austin  Cary.  of  that  place  had  gone  with  a  surveying  party  to 
near  the  head  of  the  Androscoggin  River,  and  that,  owing  to  floods 

and  log  jams  on  the  upper  streams,  some  trouble  would  be  experi- 
enced in  getting  through  to  where  he  was  located.  This  necessitated 
a  delay  of  two  days,  but  in  the  meantime  arrangements  were  made 
by  Mr.  II.  J.  Brown,  of  the  Berlin  Mills  Company,  for  transportation 
and  guides  from  the  railroad  at  Colebrook.  X.  II..  until  we  found  Mr. 
Cary. 

May  24  I  left  Portland  going  northwest  through  New  Hampshire  via 
the  White  Mountain  Notch  to  Colebrook.  Here  I  was  met  by  two 
guides  sent  over  from  Erral  with  instructions  from  the  Berlin  Mills 
Company,  and  on  May  25  we  left  Colebrook,  going  up  the  Mohawk 
River  valley  ami  through  the  Dixville  Notch  near  its  source,  thence 
down  Clear  Stream  To  Erral  on  the  Androscoggin.  Here  we  encoun- 
tered the  floods  and  log  jams  which  prevented  further  progress  by 
wagon,  and  the  remaining  distance  to  the  Brown  farm  in  Maine  was 
traversed  on  foot  and  by  canoe. 

May  26,  after  spending  a  few  hours  in  the  woods  studying  insect 
enemies  of  the  spruce,  birch,  and  fir.  we  went  on  up  the  Magalloway 
River  about  15  miles  to  the  Camp  in  the  Meadows  where  we  were  met 
by  Mr.  Cary.  The  next  morning  we  proceeded  farther  up  the  river 
to  the  Forks  Camp  near  the  mouth  of  the  Little  Magalloway.  This 
brought  us  into  the  heart  of  the  northwestern  Maine  woods  and  within 
a  few  miles  of  one  of  the  localities  in  which  the  spruce  were  dying. 

Up  to  this  time  the  route  from  Portland  through  New  Hampshire 
and  a  small  part  of  Vermont  to  Colebrook,  thence  across  northern 
New  Hampshire  and  up  the  Magalloway  in  northwestern  Maine,  led 
through  a  region  presenting  many  and  varied  features  of  New  Eng- 
land forest  conditions,  and  gave  a  good  opportunity  to  note  in  a  gen- 
eral way  some  of  the  influences  which  contribute  to  the  multiplication 
of  insect  enemies  of  trees,  as  well  as  those  which  contribute  to  their 
decrease,  or  even  the  extermination  of  certain  species  which  confine 
their  attack  to  matured  timber.     No  opportunity  was  had,  however, 


10 

to  make  a  detailed  study  of  any  of  the  problems  presented  or  sug- 
gested by  the  prevailing  conditions  until  we  reached  this  place. 

May  28  we  entered  the  undisturbed  spruce  forest  in  the  vicinity  of 
Wight's  Loggers1  camps  on  Twin  Brook,  where  the  conditions  were 
found  i<>  !>e  especially  favorable  for  commencing  the  investigation  of 
a  trouble  which  for  forty  or  fifty  years  has  attracted  so  much  atten- 
tion and  caused  the  loss  of  vasi  quantities  of  spruce  timber  in  north- 
em  New  England  and  in  New  Brunswick. 

After  spending  two  days  here  in  a  thorough  examination  of  a  large 
q umber  of  infested  living,  dying,  and  dead  trees,  which  bore  every 
evidence  of  having  been  killed  by  insects,  we  extended  our  investiga- 
tions further  into  the  forest  and  across  the  divide  to  the  Cupsuptic 
River  drainage,  and  thence  across  to  Lincoln  Pond,  where  extensive 
summer  cutting  and  peeling  of  the  timber  had  been  carried  on.  The 
examination  of  a  great  many  dying  and  dead  trees,  together  with  a 
siudy  of  the  conditions  in  the  cuttings,  left  little  doubt  as  to  the 
primary  cause  of  the  prevailing  trouble.  Indeed,  sufficient  evidence 
was  found  to  enable  me  to  suggest  to  Mr.  Cary  a  possible  remedy,  in 
providing  girdled  trees  to  attract  the  destructive  insects,  thus  con- 
centrating their  breeding  operations  in  sections  of  the  forest  where, 
by  the  ordinary  logging  operations,  the  entrapped  enemy  would  be 
transported  to  the  streams  and  thus  destroyed. 

The  following  day  we  returned  to  Wight's  Camps,  and  thence  went 
across  to  Black  Cat  Brook,  Parmacheenee  Lake,  and  Camp  Caribou. 
Three  days  were  spent  in  the  vicinity  of  this  camp,  and  on  June  4  we 
proceeded  to  the  Little  Magalloway,  and  up  this  stream  to  Hamel's 
Camp.  Thence  the  next  day  we  went  to  near  its  source  and  the  sum- 
mit of  Rump  Mountain.  This  route,  leading  as  it  did  through  an 
extensive  burned-over  area,  recent  cuttings,  and  undisturbed  forest, 
where  much  dying  and  dead  timber  was  found,  gave  an  excellent 
opportunity  for  the  successful  prosecution  of  the  investigations.  The 
observations  we  were  enabled  to  make  from  the  summit  of  the  moun- 
tain were  also  of  especial  interest  and  importance. 

We  returned  to  Camp  Caribou  June  7,  where  I  was  joined  by  Mr. 
Henry  Carter,  who  had  instructions  from  Mr.  Cary  to  accompany  me 
on  an  exploration  in  the  heart  of  the  wilderness  north  of  Camp  Cari- 
bou. We  started  on  June  8,  going  to  Little  Boys'  Falls  on  the  Magallo- 
way; i  hence  by  trail  and  canoe  to  and  above  .Moose  Bog  Camp,  and 
i  hence  by  trail  via  the  Game  Keeper's  Camp  to  Barkers  Lake,  which 
is  located  near  the  Canadian  line  and  forms  the  principal  source  of 
the  Magalloway.  From  here  we  returned  by  trail  to  Lower  Black 
Camp  and  theuce  to  Camp  Caribou,  where  we  arrived  in  the  evening 
of  June  1 1. 

This  trip  enabled  me  to  gather  much  valuable  information  relating 
to  the  distribution  of  the  trouble;  the  condition  of  the  timber  that 
had  been  dead  live  to  twenty  years;  and  the  relations  of  old  cuttings, 


11 

blow-downs,  and  other  prevailing  features  which  had  a  direct  bearing 
on  the  problem  under  investigation. 

Mr.  Gary  joined  me  again  at  Camp  Caribou,  aud  June  13  we  pro- 
ceeded by  the  old  Danforth  trail  to  the  Cupsuptic  River,  and  thence 
to  the  Stonehouse  on  the  lake  near  its  mouth.  From  here  we  pro- 
ceeded up  the  Kennebago  River  and  devoted  several  days  to  the 
exploration  of  the  great  spruce  region  at  the  sources  of  this  and  Dead 
River.  This  also  included  a  climb  to  the  summit  of  Boil  Mountain 
where,  as  from  Rump  Mountain,  an  excellent  view  was  had  of  the 
prevailing  conditions  as  to  dead  and  living  timber  over  a  vast  extent 
of  forest. 

Between  Kennebago  Lake  and  Beaver  Pond  we  had  a  good  oppor- 
tunity to  study  the  conditions  in  the  historic  blow-downs  of  1871  and 
1883,  which  were  followed  by  great  invasions  of  spruce-destroying 
insects. 

We  returned  to  the  Cupsuptic  Juue  17,  and  next  day  I  returned  to 
Brunswick  and  Portland.  After  making  some  investigations  on  Peak 
Island  and  in  the  vicinity  of  Portland,  and  reporting  to  the  Berlin 
Mills  Company  some  features  of  the  results  of  my  investigations  in 
sections  of  the  Androscoggin  region  in  which  they  were  specially 
interested,  I  returned  home,  where  I  arrived  June  29. 

The  specimens  of  insects  and  their  work  collected  on  this  trip  num- 
bered something  over  1,700,  including  44  species  from  the  Red  Spruce, 
six  from  the  White,  and  nine  from  the  Black. 

THE  ANDROSCOGGIN  REGION  AND  ITS  SPRUCE  FORESTS. 

The  Androscoggin  drainage  north  of  the  Rangeley  Lakes  and  west 
of  the  headwaters  of  the  Dead  River  of  the  Kennebec,  in  which  the 
investigations  were  conducted,  is  one  of  great  interest,  and  since  the 
varied  conditions  prevailing  there  have  a  direct  bearing  on  the  prob- 
lems to  be  discussed  further  on  in  this  report,  it  seems  fitting  and 
proper  that  some  space  should  be  devoted  to  its  discussion.  In  this 
I  can  do  no  better  than  to  quote  from  the  writings  of  Mr.  Cary,  than 
whom  there  is  probably  no  better  authority.  Indeed,  after  having 
gone  over  the  territory  with  him  I  learned  to  have  much  confidence 
in  his  ability  as  a  practical  expert  forester  and  a  careful  and  accurate 
observer  of  forest  conditions.1 

'  *  *  *  These  townships  [Grafton,  Andover.  North  Surplus,  Letters  D  and  E. 
and  No.  6]  that  I  have  referred  to  form  a  barrier  separating  the  upper  from  the 
lower  course  of  the  Androscoggin.  To  the  §outh  is  the  lower  river,  flowing 
approximately  east  for  50  miles,  catching  streams  from  both  sides  of  its  coarse. 
To  the  north  of  that  barrier  lies  the  Rangeley  Lakes  system,  again  with  its  axis 
east  and  west  and  about  30  miles  in  length.  The  lakes,  therefore,  situated  as  they 
are  close  under  this  mountain  barrier,  receive  only  trifling  tributaries  from  the 
south.     Their  volume  is  chiefly  maintained  from  the  country  to  the  north,  which 


1  Paper  by  Mr.  Austin  Cary,  in  Third  Annual  Report  of  the  Forest  Commissioner 
of  Maine,  pp.  127, 128.  1S96. 


12 

drains  into  them  by  three  considerable  streams— the  Magalloway,  the  Cupsuptic, 
and  the  Kennebago.  The  outlet  of  the  system  is  at  the  west  where  the  river  forces 
a  way  tor  Itself  close  under  the  eastern  faceof  the  White  Mountains.  Attheeast, 
OH  the  other  hand,  the  upper  lakes  are  closely  approached  on  the  high  but  elevated 
land  by  the  headwaters  of  the  Dead  and  Sandy  rivers,  which  run  into  the  Ken- 
nebec. 

Now.  as  the  Rangeley  Lakes,  with  the  exception  of  Umbagog.  are  about  1,400 
feet  above  the  sea.  while  the  country  about  is,  much  of  it,  considerably  higher, 
this  Upper  Androscoggin  country  is  more  elevated  than  any  other  area  of  equal 
size  within  the  limits  of  the  State. 

Here  on  the  headwaters  of  the  Androscoggin  is  the  chosen  home  of  the  spruce. 
Continuous  with  the  high  land  of  northern  New  Hampshire,  a  part  of  the  great 
White  Mountain  plateau,  this  region  in  its  elevation,  its  uneven  topography,  and 
its  climate  seems  to  afford  that  combination  of  conditions  which  ministers  to  the 
perfect  development  of  the  spruce.  The  timber  of  the  Appalachian  Mountains 
farther  south  is  not  known  to  the  writer.  It  is  a  fact,  however,  that  no  other 
part  of  Maine  ever  had  any  such  spruce  stand,  and  probably  no  portion  of  New 
York  or  New  England  as  is  found  from  here  across  northern  New  Hampshire. 
Only  patches  of  timber  elsewhere  stand  as  thick  as  does  the  country  here.  Much 
of  the  timber  too  is  of  the  finest  quality  and  size.  * 

Returning  again  to  Parkertown,  let  me  present  some  figures  that  will  be  used 
in  a  further  discussion  of  the  problems  arising  in  connection  with  the  manage- 
ment of  the  Androscoggin  land.  First  is  the  detailed  statement  of  the  trees 
standing  on  a  sample  acre  that,  fairly  representative  of  the  country  in  its  stand 
ot  merchantable  spruce  timber,  was  thought  to  be  appropriately  such  also  in 
respect  to  the  proportion  of  hard  and  soft  wood  in  large  and  small  trees.  Note 
particularly  the  number  of  large  spruce  trees  as  compared  with  those  from  6  to 
12  inches  in  diameter.  Their  relation  is  no  chance  or  insignificant  matter.  Much 
study  has  shown  it  to  be  characteristic  of  typical  Androscoggin  spruce  land, 
while  from  it  are  drawn  hereafter  important  practical  conclusions: 

Trees  standing  on  an  acreof  uncut  lain!  in  Townships,  Ranges,  Oxford  County. 


Spruce. 

<  tther  species. 

Diameter. 

i 

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I 

o5 

s 

= 
> 

to 

w 

Diameter. 

4 

3 

O 

Q 
1* 

i 

6 
P. 

Kst  i  7nated 
volume. 

Estimated 

scale. 

Inches. 

(  >V.T    IS' 

14 
11 

0 

8 
is 
8 

as 

'.Ml 

Feet.        (■«.  ft. 
70-90           l.OtHi 
7(1  80               600 
60-75             210 
60-66             135 
in  50              170 
;>.-.  »:>             35 

4U 

Ft.B.M. 
3,500 

:i.(NH) 
840 
502 
510 

Inches. 
Over  18... 

11  Lfi 

12-14 

lOandll.. 
Band  9.... 
•land  7.... 

8-6 

Under :: 

Total. 

11 

6 

•-' 

4 
3 
3 

8 

4 

2 
3 

:; 

o 

1(1 
.-.".I 

4 
6 

8 
i:i 
3 

4 

1 

.... 

:; 

44 

L66 

On.  it. 

1,000 

400 

200 

Ft.  B.  M. 

15  18« 

1:.'  11 

:::::::::: 

10 and  ll  i 

300 
200 

50 

i:*o 
90 

B  and  9 

6  and  '. 

Cn. I. 

10 

Total 

191 



2,280 

7.352 

41 

49 

40 

:.'l  1 

2,800 

4.000 

1  <  >ne  worthless  tree  In  each  class. 


In  the  estimated  scale  put  upon  the  sample  acre  -about  7,400  feet— 
5,500,  <»r  three-quarters  of  the  whole,  was  in  the  shape  of  trees  over  14  inches 
in  diameter  I  feet  from  the  ground.  That  is  a  fact  to  be  distinctly  marked. 
Three-quarters  of  the  total  spruce  in  the  natural  stand  of  the  country  is  mature — 
ready  in  the  natural  course  of  things  to  be  cut.  Tins  is  not  merely  the  lumber- 
man's interest     It  is  the  States  interest.     In  timber  like  this,  growth  is  balan<  ed 


13 

by  decay.  Dead  trees  stand  scattered  throughout  it.  Upon  this  very  acre  there 
was  one.  Several  more  were  dying  or  imperfect,  while  doubtless  several  of  the  '-28 
full-grown  trees  scored  are  every  year  decreasing  in  value.  These  large,  old  trees. 
too,  cumber  the  ground.  Producing  little  themselves  they  yet,  by  their  shading, 
keep  down  the  young  growth,  which  could  make  good  use  of  the  room.  No  one 
can  dispute  the  lumberman's  right  or  interest  in  regard  to  these  trees. 

*  *.  *  The  Androscoggin  drainage,  from  the  spruce  point  of  view,  is  the  best 
worthy  of  study  of  all  the  rivers  of  the  State.  It  is  also  the  one,  in  my  judgment, 
on  which  a  conservative  forest  policy  is  likely  to  go  first  into  effect. 

In  a  letter  to  Mr.  Cary,  Mr.  J.  A.  Pike  estimates  that  the  spruce 
then  (December,  1895)  standing  in  the  Androscoggin  basin,  at  and 
above  Berlin,  Me.,  was  3,000,000,000  feet.     He  says: 

This  estimate  is  based  largely  on  personal  examination  and  entirely  upon  per- 
sonal knowledge  of  the  territory  and  th6  character  of  the  growth,  and  after 
consulting  notes  and  memoranda  extending  over  a  period  of  more  than  twenty 
years. 

Mr.  Cary  again  refers  to  the  spruce  of  Maine  in  a  paper  read  before 
the  Boston  Society  of  Civil  Engineers,  May  10,  1800, »  as  follows: 

It  seems  probable,  then,  that  25,000,000.000  feet,  board  measure,  may  approxi- 
mate the  amount  of  spruce  woods  standing  in  the  State.  The  total  lumber  cut  in 
the  State  in  1896  was  something  over  600.000,000  feet.  Of  this,  probably  500,000,000 
feet  was  spruce.     About  two-fifths  of  this  went  to  the  paper  and  pulp  mills. 

Six  hundred  million  feet  is  equivalent  to  30  feet  per  acre  on  the  gross  area  of  the 
State.  Five  hundred  million  feet  may  be  50  feet  per  acre  on  the  area  of  what  we 
might  call  spruce-producing  land.  These  figures  are  within  the  amounts  which 
such  stands  as  have  been  made  attached  to  ordinary  cut-over  land  as  its  yearly 
growth.  Certain i y  they  are  small  in  comparison  to  what  we  know  that  scientific 
forestry  has  produced  elsewhere. 

The  general  inference  to  be  drawn  from  these  facts  is  not  a  discouraging  one. 
Our  resources  are  still  great,  and  we  may  feel  justified  in  using  them  freely. 

At  present  the  botanists  recognize  three  distinct  species  of  spruce 
from  New  England,  the  Red  (Picea  rubens),  the  White  (Picea  cana- 
densis), and  the  Black  (Picea  montana)  (Plate  I),  all  of  which  were 
noted  by  the  writer  and  their  insect  enemies  studied. 

One  of  these,  the  Red  Spruce,  on  account  of  its  size,  great  value, 
and  prevalence  throughout  the  spruce  area,  is  recognized  commer- 
cially as  "The  Spruce,"  while  the  others,  from  an  economic  stand- 
point, are  of  secondary  or  minor  importance. 

DEAD  AND  DYING  SPRUCE. 

The  prevailing  condition  which  attracts  especial  attention  in  the 
upper  Androscoggin,  is  the  large  amount  of  dead  spruce.  It  stands 
in  clumps  of  a  few  trees  to  several  hundred,  and  as  individuals  scat- 
tered through  the  forest,  or  left  in  the  cuttings.  In  some  places  the 
old-felled  trunks  and  tops  make  travel  through  the  woods  exceed- 
ingly difficult. 

'Jour.  Assoc.  Eng.  Soc.  Vol.  XXIII.  No.  3,  Aug.,  1899,  p.  5. 


14 

While  r  large  amount  of  dead  spruce  was  observed  throughout  the 
area  traversed,  thai  which  was  then  dying,  or  had  died  within  the  past 
one  i«»  four  <>r  Ave  years,  is  Limited  to  well-defined  areas  of  greater  or 
Less  extent,  in  different  sections,  bu1  always  involving  the  best  stands 
and  Largest  t  Lmber. 

The  dead  Bpruce  is  not  confined  to  any  particular  condition  of  soil, 
exposure,  or  altitude,  but  is  found  under  all  conditions,  from  bogs  to 
high,  exposed,  rocky  slopes,  or  whenever  the  trees  attain  a  diameter 
of  over  1-  inches. 

SOME    CHARACTERISTICS   OF   THE   DYING   AND   DEAD   SPRUCE. 

When  the  t  pees  commence  to  die,  the  first  indication  in  their  general 
appearance  is  a  pale  tint  of  the  leaves  on  the  upper  branches  and  tops. 
These  soon  fall,  even  before  they  lose  their  green  color.  When  the 
trees  are  in  this  stage  of  decline,  the  winder  a  slight  jar,  as  witli  an 
ax,  will  cause  a  shower  of  the  needles  to  fall,  and  the  ground  will  be 
covered  with  them.  After  the  leaves  have  fallen,  the  dead  twigs 
present  a  reddish  appearance,  rendering  them  quite  distinct  and  easily 
recognized  from  a  distance,  when  viewed  from  an  elevated  point. 
They  gradually  assume  a  Light-gray  appearance,  followed  by  a  darker 
gray;  then,  a  few  years  later — the  actual  time  not  yet  determined — 
the  twigs  begin  to  fall;  Later  the  branches,  and  still  later  the  tops 
break  off.  Finally,  after  many  years — ten  to  twenty  Or  more,  depend- 
ing on  the  soundness  of  the  base  and  roots — the  decaying  trunk  will 
topple  over,  and  contribute  to  the  food  supply  of  the  young  genera- 
tion of  trees,  which  have  sprung  up  to  utilize  the  sunlight  thus  made 
available. 

Trees  with  diseased  roots  usually  fall  before  they  have  lost  their 
small  branches,  and  the  wood  probably  decays  far  more  rapidly  than 
in  those  with  sound  roots. 

The  only  way  the  declining,  dying,  and  recently  dead  trees  can  be 
recognized  from  the  trail,  or  in  going  through  the  woods,  when  the 
tops  come  between  the  observer  ami  the  sky,  is  by  the  fine  dust  in  the 
outer  bark  and  moss  near  the  base,  the  pitch  tubes  on  the  bark  from 
near  the  base  up  to  10  or  20  feet,  the  falling  or  fallen  leaves,  or  the 
work  of  woodpeckers.  The  removal  of  the  outer  bark  by  the  birds  in 
search  of  insects  makes  the  reddish  inner  bark  conspicuous,  even  on 
living  tires,  when  they  show  no  other  indication  of  decline.  Indeed, 
the  tiers  on  which  the  birds  have  been  at  work  stand  out  distinct,  and 
can  1m-  seen  for  a  long  distance  in  the  woods. 

CAUSES   OK    DECAY    AND    DEATH. 

There  are  iw<>  causes  of  decay  and  death,  one  or  both  of  which 
affected  each  of  the  many  hundreds  of  trees  examined:  (1)  The  work 
of  an  insect  in  the  bark  on  the  middle  trunk,  causing  the  death  of  the 


15 

tree;  (2)  the  presence  of  fungi  in  the  bark  and  wood.  The  latter  lias 
been  investigated  by  Dr.  Herman  von  Schrenk,  for  the  Division  of 
Vegetable  Physiology  and  Pathology,  and  his  report  has  appeared  in 
a  bulletin  of  that  Division.  Therefore,  only  such  reference  will  be 
made  to  these  diseased  conditions  as  has  a  direct  or  interrelated  bear- 
ing on  the  insect  problem,  and  methods  of  preventing  losses  from 
their  combined  attack. 

RELATION    OF   INSECTS   TO   THE    TROUBLE. 

With  very  few  exceptions x  all  of  the  great  number  of  affected  trees 
examined,  which  were  in  all  stages,  from  living  to  old  dead  ones, 
throughout  the  area  covered  by  the  trip,  showed  evidence  of  depreda- 
tion by  insects;  and  in  nearly  every  case  quite  conclusive  evidence 
was  found  that  one  species,  a  bark-mining  beetle,  had  been  or  was 
then  associated  with  the  primary  cause  of  these  unhealthy  conditions 
and  death.  This  evidence  consisted  in  the  healed-over  burrows  in  the 
living  bark  of  healthy,  vigorous  trees;  in  broods  of  this  insect  which 
had  developed  in  the  bark  of  living  trees  during  the  summer  of  1899, 
the  trees  yet  living  in  May  and  June,  1900;  in  the  hundreds  of  dying 
and  dead  trees,  with  vast  numbers  of  all  stages,  from  young  larva?  to 
adults,  of  this  insect  under  the  bark,  where  they  bred  the  previous 
summer  and  fall;  and  finally  its  characteristic  galleries  in  the  bark, 
or  on  the  surface  of  the  wood  of  old  dead  trees  which  had  been  dead 
from  ten  to  twenty  years,  while  the  logs,  stumps,  and  tops  in  cuttings 
showed  little- evidence  of  its  attacks. 

In  addition  to  this  common  and  primary  enemy  of  the  spruce,  many 
other  species  of  bark  beetles,  flat-headed  and  round-headed  bark  and 
wood  borers,  occurred  in  the  dying  and  dead  trees,  some  following 
closely  the  first  attack  by  the  primary  enemy,  others  coming  later, 
and  still  others  in  succession  until  the  last  vestige  of  the  bark  and 
wood  is  converted  back  to  earth. 

THE  SPRUCE-DESTROYING  BEETLE. 

The  observations  of  the  writer  lead  him  to  conclude  that  of  all  the 
insect  enemies  of  the  spruce,  this  beetle  must  take  first  place  as  the 
most  destructive.     It  is  the  leader  in  the  attack,  while  the  others, 

1  In  all  forests,  and  especially  those  in  undisturbed  or  natural 'condition,  a  cer- 
tain percentage  of  trees  seem  to  die  naturally.  While  there  is  no  such  thing,  per- 
haps, as  a  natural  deathot  a  tree,  there  are  those  which,  in  their  struggle  for  exist- 
ence with  their  many  younger  and  more  vigorous  competitors,  become  weakened 
in  their  vita.ity  and  thus  are  more  susceptible  to  the  attack  of  their  numerous 
enemies  among  insects  and  fungi,  and  also  to  the  injurious  effects  of  unfavorable 
climatic  conditions,  which,  combined,  cause  them  to  die.  Trees  perishing  in  this 
manner,  however,  occur  as  isolated  individuals,  scattered  throughout  the  forest, 
and  seldom,  if  ever,  in  clumps. 


16 

found    in   the   bark   and   wood,  arc   followers,  allies,  dependents,  or 

natural  enemies  of  one  or  more  of  tin*  hark  and  wood  miners. 


DESCRIPTION    OF   THE    DESTROYER. 


This  insect  belongs  t<>  the  order  Coleoptera,  the  true  beetles,  which 
are  most  distinguished  in  a  general  way  by  their  hard  wing  covers. 
Ii  belongs  to  the  family  of  beet  Lee  known  as  Seolyl  idae  and  to  i  he  genus 
Dendroctonus.  dp  to  the  present  lime  it  has,  together  with  several 
other  distinct  but  closely  allied  forms,  been  recognized  by  entomolo- 
gists under  the  specific  name  ri/fi /it  nn is,  a  name  that  was  applied  by 
the  English  entomologist,  William  Kirby,  to  a  species  described  by 
him  in  L835  from  specimens  collected  on  a  journey  from  New  York 
state  to  the  shores  of  Hudson  Hay.  It  has  been  determined,  however, 
by  comparison  with  the  original  specimens  now  in  the  British  Museum 
collections,-  that  the  spruce-destroying  beetle  is  quite  distinct,  and  I 
have  applied  to  it  the  name  Dendroctonus  piceaperda,  meaning  spruce 
destroyer. 

Tht  ad ult  (PI,  II,  figs.  1,  2)  varies  in  length  from  three-sixteenths 
to  five-sixteenths  inch  (4.7  to  5mm.),  and  in  width  from  one-sixteenth 
to  nearly  two-sixteenths  inch  (1.1)  to  2.6  mm.).  It  also  varies  in  color 
from  Light  yellowish  in  the  younger  specimens  to  dark  reddish-brown 
and.  in  some  mature  individuals,  nearly  black.  It  will  be  more  readily 
recognized  by  the  general  observer  from  its  common  occurrence  in  the 
bark  of  dying  and  recently  dead  spruce  trees;  also  by  the  character 
of  its  work,  described  and  illustrated  further  on. 

Tht  egg  is  a  small  pearly  white  object,  scarcely  to  be  distinguished, 
if  at  all,  from  those  of  other  bark  beetles  of  the  same  size. 

Tin  larva  is,  upon  hatching  from  the  egg,  a  minute,  white,  legless 
grub  (PI.  II,  tig.  4),  which  feeds  on  the  inner  bark  and  increases  in 
size  until  it  has  attained  a  diameter  equal  to  that  of  the  adult  ami  a 
length  somewhat  greater.  It  maybe  distinguished  from  any  other 
similar  larva  as  yet  found  in  the  Eastern  spruce  by  a  dark  yellowish- 
brown  space  on  the  upper  surface  of  each  of  the  last  two  abdominal 
segments  (PL  II,  fig.  4^). 

Thi  pupa  (PI.  II,  fig.  3)  is  nearly  white,  of  the  same  size  and  some- 
what the  same  form  as  t  he  adult ,  but  without  free  legs  and  wings,  and 
is  found    in  oblong  cavities  in  the   bark  of  the  trees  where  the  broods 

develop. 


1  Detailed  technical  descriptions  will  appear  in  a  special  paper  to  be  published 
later. 

BCimens  of  the  Dendroctonus  collected  from  spruce  in  Maine,  together  with 
specimens  of  another  species  from  Hudson  Bay  and  Lake  Superior  regions,  were 
sent  to  the  British  Museum  and  were  compared,  by  Mr.  Charles  O.  Waterhouse, 
With  Kirby  "s  types.  He  found  that  the  one  from  Lake  Superior  agreed  with  the 
labeled  specimen,  the  our  from  Hudson  Bay  agreed  with  another,  and  the  speci- 
men* from  Maine  were  different  from  any  in  the  type  series. 


17 

LIFE    HISTORY    OF   THE    BEETLE. 

The  time  of  year  when  the  investigation  was  made  was  especially 
favorable  for  studying  the  hibernating  habits  of  this  insect,  and 
enabled  the  writer  to  commence  a  study  of  its  life  history  with  the 
later  part  to  the  close  of  its  dormant  or  inactive  period. 

HOW    IT    PASSES    THE    FALL,  WINTER.  AND   SPRING. 

The  fall,  winter,  and  spring,  and  part  of  the  first  summer  month 
are  passed  in  all  stages  of  the  larva,  from  quite  small  to  full  grown, 
as  well  as  in  the  adult  stage,  developed  the  preceding  summer  or  fall. 

So  far  as  could  be  determined  by  the  writer,  the  eggs  deposited  too 
late  in  the  fall  to  hatch  before  cold  weather  sets  in.  the  pupae  that 
develop  too  late  to  change  to  the  adult,  and  some  of  the  very  young 
and  tender  adults,  do  not  survive  through  the  winter. 

The  adults  hibernate  in  the  bark  and  usually  but  a  short  distance 
from  where  they  were  located  when  the}'  transformed  from  the  pupae 
or  where  the  winter  found  them  in  their  primary  galleries.  The 
larva?  are  found  in  their  mines,  where  they  ceased  feeding  in  the  fall. 
The  very  young  to  nearly  matured  larva?  are  often  found  in  living- 
bark,  while  the  developed  broods  of  the  adults  are  nearly  always  in 
bark  which  has  recently  died.  In  some  trees  many  dead  adults  were 
found,  which,  owing  to  some  unfavorable  condition,  probably  within 
the  bark  itself,  had  died  or  been  killed  by  the  winter  freezing,  while 
in  the  greater  number  of  infested  trees  all  stages  but  the  eggs  and 
pup*,  had  not  been  injured  in  the  least:  indeed,  they  seemed  to  be  in 
as  perfect  health  as  when  they  ceased  activity  in  the  fall. 

WHEN    ACTIVITY    COMMENCES    IN    THE    SPRINO. 

When  the  first  individuals  were  seen  on  May  28,  near  north  latitude 
45  .  and  at  an  altitude  of  about  2,000  feet,  all  of  the  hibernating  stages 
were  inactive.  This  condition  continued  until  about  June  -i,  when 
warmer  weather  set  in  and  indications  of  activity  were  noted.  On 
June  5,  at  Hammel's  Camp,  on  the  Little  Magalloway,  the  matured 
larvae  were  found  to  be  almost  ready  to  change  to  the  pupa?.  The 
next  day,  in  the  same  locality,  numerous  pupa?  were  observed,  which 
had  just  transformed  from  the  larval  stage.  From  that  day  on  to 
June  17  the  pupa?  were  commonly  met  with  and  the  young  larva?  were 
apparently  feeding.  Toward  the  13th  the  adults  showed  evidence  of 
uneasiness,  as  if  preparing  to  emerge,  and  the  first  one  of  the  season 
was  observed  excavating  an  entrance  in  the  living  bark  of  a  healthy 
spruce.  I  was  not  positive,  however,  that  it  had  not  commenced  this 
excavation  last  fall  and  remained  in  it  over  winter.  Indeed  none 
were  observed  flying  then  or  up  to  the  time  the  last  observations  were 

3500— No.  28—01 2 


18 

made. just  before  my  Leaving  thai  region  on  June  17.  It  is  therefore 
possible  that  some  individuals  pass  the  dormant  period  in  the  outer 
hark,  where  they  had  commenced  to  excavate  entrances  in  the  fall. 

THE   SUMMER   PERIOD. 

Iii  the  course  of  Mr.  Cary's  observations  in  connection  with  the 
girdling  experiments  some  important  information  relating  to  the  Life 
history  of  tins  beetle  was  noted  by  him.  According  to  his  notes  the 
beetles  eominenced  to  emerge  about  the  middle  of  June.  Galleries 
had  been  excavated  in  some  of  the  girdled  trees  and  eggs  were  depos- 
ited by  June  1  !>.  The  first  larvae  were  noticed  on  July  28  to  31.  Pupae 
were  eoniinou  on  September  I,  with  a  few  recently  developed  beetles, 
and  on  October  4  many  of  the  beetles  had  fully  matured,  but  none  had 
emerged.  It  is  therefore  probable  that  the  beetles  will  not  emerge 
and  attack  other  trees  before  the  following  summer,  although  a  few 
early  developed  beetles  may  emerge  in  October  and  enter  the  outer 
bark  of  living  trees. 

Mr.  Cary's  observations  furnish  quite  conclusive  evidence  that  in 
northwestern  Maine  there  is  but  one  brood  in  a  season,  even  from  the 
hibernating  adults,  and  that  the  period  of  development  from  the  ey:g 
to  the  adult  is  about  seventy  to  seventy-five  days — from  the  middle  of 
.1  une  to  the  last  of  August. 

SUMMARY   OF   LIFE   HISTORY. 

These  observations  would  also  indicate  that  activity  ceases  in  the 
fall  by  about  the  middle  of  October,  when  all  stages  of  the  insect  may 
occur  in  the  bark  of  infested  trees  where  they,  with  the  probable 
exceptions  of  the  eggs  and  pupse,  remain  until  the  first  week  in  June. 
Activity  then  commences,  the  mature  larvse  change  to  pupa3,  and  by 
the  middle  of  June  those  that  pass  the  winter  in  the  adult  stage  emerge 
and  commence  to  excavate  galleries  and  deposit  eggs.  The  adults 
from  the  hibernating  larv«  of  different  stages,  develop  and  continue 
to  emerge  possibly  until  the  last  of  August.  Therefore  the  eggs 
deposited  by  the  late-developing  beetles  produce  larva?  which  do  not 
complete  their  development  until  July  or  August  of  the  nexi  year. 
Thus,  the  period  of  development  may  vary  from  about  seventy  daj^s 
to  about  twelve  months,  but  all  broods  from  eggs  to  matured  and 
emerging  adults  remain  in  the  bark  about  twelve  months,  of  which 
they  arc  dormant  about  seven  and  one-half  and  active  four  and  one- 
half. 

The  following  diagram  will  indicate  the  probable  normal  rate  of 
development  from  the  different  hibernating  stages: 


19 


EXPLANATION    OF     DIAGRAM. 

The  accompanying  di- 
agram (fig.  1)  illustrates 
the  dormant  and  active 
periods  and  the  rate  of 
development  of  Deit- 
droctonus  piceaperda. 
The  symbols  at  the  left 
represent  the  different 
stages  of  the  insect  in 
the  bark  of  infested 
trees  when  activity 
ceases,  about  the  mid- 
dle of  October:  (•)  rep- 
resents the  mature,  im- 
mature, and  very  young 
adults:  (O)  represents 
thepnpse;  (°  o  O)  rep- 
resent three  stages  of  the 
larva-,  and  (•)  the  eggs. 

Commencing  with  the 
mature  adults,  in  the 
upper  line,  the  normal. 
or  average,  dormant  and 
active  periods,  and  the 
periods  of  development 
are  represented  as  fol- 
lows: The  dormant  pe- 
riod of  two  hundred  and 
thirty-two  days  ends 
about  the  5th  of  June: 
in  about  ten  days  more 
the  adults  commence  to 
emerge:  in  twenty  days 
eggs  are  deposited:  in 
thirty  days  larvae  com- 
mence to  appear :  in  sixty 
days  the  larvae  are  ma- 
tured: in  sixty-five  days 
pupa*  commence  to  de- 
velop: and  in  eighty 
days  from  the  time  ac- 
tivity commences  the 
first  adults  develop; 
they  probably  continue 


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to  develop  until  toward  the  last  of  September,  but  they  remain  in 
the  bark  until  activity  ceases.  The  hibernating,  unmatured,  and  very 
young  adults  appear  ten  i<>  twenty  days  Later  than  the  fully  matured 
ours;  they  continue  t<>  emerge  and  deposit  eggs  until  about  the  lasi 
of  July. 

The  few  pupa'  present  when  activity  ceases  evidently  perish  by  the 
Last  of  January,  as  do  also  the  eggs. 

The  three  stages  of  hibernating  Larvae  develop  to  adults  after 
activity  commences  in  1 1 1 < *  same  ratio  as  the  hibernating  adults,  but 
owing  to  retarded  development  some  of  them  probably  do  not  attain 
the  adult  stage  until  Late  in  September.  Thus  adults  would  be  com- 
ing out  during  the  entire  period  of  activity,  which  accounts  for  the^ 
existence  of  all  stages  when  activity  ceases  in  the  fall. 

SPECIAL   FEATURES   OF   THE   BEETLE'S   WORK. 
KINDS   OF   TREES   ATTACKED. 

So  far  as  known  this  beetle  attacks  only  the  spruce,  and  the  most 
striking  and  important  feature  is  its  habit  of  attacking  only  the 
Larger  trees.  It  is  rarely  found  in  trees  below  L0  inches  in  diameter 
breast-high,  but  in  all  infested  areas  is  exceedingly  common  in  those 
over  IS  inches  at  the  same  height.  It  also  appears  to  have  a  decided 
preference  for  standing  trees,  although  some  evidence  was  found  that 
it  will  breed  in  wind-felled  trees  and  rarely  in  stumps  and  logs  in 
cuttings. 

HOW   AND  WHEN   THE   ATTACK    IS   MADE. 

A  study  of  the  living  trees  which  had  recovered  from  a  slight  at  lack, 
as  well  as  those  that  were  infested  by  different  stages  of  the  insect, 
indicated  quite  clearly  that  the  first  entrances  are  made  in  the  bark 
of  the  healthy  tree  at  a  point  from  6  to  10  feet  from  the  base,  and  that 
trees  which  are  weakened  in  vitality  from  disease  or  other  causes  may 
be  attacked  from  near  the  base  to  near  the  first  large  branches. 

The  fact  that  as  a  rule  the  infested  trees  are  found  in  clumps  or 
confined  to  definite  areas  of  greater  or  less  extent  would  indicate  a 
social  habit,  and  that  the  individuals  may  migrate  in  swarms  from  an 
old  to  a  new  locality  and  settle  without  any  special  choice  except  as 
to  size  or  number  of  trees.  Thus  they  invade  the  trees  on  all  sides, 
and  usually  in  such  numbers  as  to  prevent  recovery  from  the  first 
attack.  As  soon  as  the  t  rees  commence  to  decline  they  are  invaded 
by  ol  her  bark-mining  beetles  and  grubs,  which  aid  in  their  final  death 

and  decay. 

ITS    WORK    IN    AND    BENEATB    THE    BARK. 

Tht  i  iiir<iii<-i  anil  fin  primary  gallery. — This  is  started,  probably 

by  the  male,  hidden  in  a  ereviee  or  beneath  a  (lake  of  bark,  and,  if  in 

a  living  tree,  Is  gradually  and  obliquely  extended  upward  or  to  one 
side  through  the  inner  bark.     The  male  is  then  joined  by  a  female, 


21 

and  together  they  excavate  a  broad  primary  or  egg  gallery  (PI.  Ill) 
up  through  the  inner  bark,  often  grooving  the  surface  of  the  wood, 
for  a  distance  of  from  2  to  0  inches.  Along  the  sides  of  this  gallery, 
which  is  usually  about  three  times  as  broad  as  the  beetle,  the  eggs 
are  placed  singly  in  small  cavities  or  in  groups  along  a  notched 
groove.  The  eggs  are  then  protected  by  a  mass  of  borings  cemented 
with  gum,  which  are  closely  packed,  filling  up  the  broad  egg  gallery, 
with  the  exception  of  a  small  central  burrow  which  is  left  or  is  subse- 
quently excavated  through  the  middle  of  its  entire  length.  The 
original  entrance  is  first  packed,  then  an  opening  to  the  outside  is 
made  in  the  roof  of  the  gallery  a  few  inches  from  the  entrance, 
another  section  is  excavated  and  packed  and  another  hole  is  made 
through  the  roof,  and  so  on  until  the  gallery  is  completed.  After  all 
is  finished  the  adults  make  one  or  two  irregular  lateral  branches  at 
the  farther  end,  apparently  for  an  abiding  place  until  they  die. 

The  gum  flowing  into  the  wound  made  by  the  beetle  when  it  is 
excavating  the  entrance  is  pushed  out  and  a  hole  kept  open  through 
it,  thus  forming  what  is  known  as  pitch  rubes,  which  are  so  conspicu- 
ous on  the  bark  of  recently  attacked  trees.  After  the  vitality  of  a 
tree  is  weakened  by  numerous  wounds  and  an  excessive  flow  of  resin, 
the  entrances  subsequently  made  are  not  marked  by  pitch  tubes;  or 
if  a  tree  is  decidedly  weakened  from  other  causes  before  it  is  attacked, 
pitch  tubes  will  not  be  formed. 

When  numerous  beetles  are  boring  into  the  outer  bark  the  dry  dust 
falls  down  and  lodges  in  the  flakes  of  bark  and  the  moss  on  the  tree, 
so  that  a  freshly  attacked  tree  may  be  identified  from  its  presence. 

The  secondary  or  larval  mines. — When  the  eggs  hatch,  the  minute 
white  grubs  or  larva?  eat  their  way  into  the  soft  inner  bark,  which  by 
this  time  has  commenced  to  die  and  is  in  the  best  condition  for  their 
food  supply.  When  the  eggs  are  placed  in  separate  cavities  each 
larva  makes  a  separate  mine,  but  when  the}'  are  massed  along  the 
sides,  or  placed  close  together,  they  work  side  by  side  and  consume 
all  of  the  inner  lajer  of  bark  until  they  have  progressed  some  dis- 
tance, when  they  begin  to  separate  and  each  larva  makes  an  inde- 
pendent mine.  (PL  IV.)  While  the  individual  burrow  may  cross 
and  recross  those  of  its  neighbors,  it  preserves  a  course  of  its  own 
and  increases  in  width  as  its  occupant  increases  in  size  until  the  larva 
attains  its  full  size  and  ceases  to  feed.  It  then  excavates  a  cavity 
neither  in  the  bark  next  to  the  wood  or  next  to  the  outer  dry  bark, 
where  in  due  time  it  changes  to  the  pupa.  Here  it  remains  in  a  semi- 
dormant  condition  until  the  legs,  wing  covers,  and  other  parts  develop. 
It  then  sheds  its  outer  skin  and  becomes  an  adult  winged  beetle,  soft 
and  yellow  at  first  but  gradually  hardening  and  becoming  darker.  In 
due  time  the  mature  beetle  bores  its  way  out  to  the  surface  and 
emerges  to  fly  about  in  search  of  a  tree  in  which  to  excavate  galleries 
for  another  brood. 


22 

Till.    DISTINCTIVE,    Visll'.LK    EVIDENCES    OK  THE   SPRUCE   DESTROYER'S 

WORK. 

The  characteristic  features  which  arc  of  considerable  importance  to 
the  forester  and  Lumberman  in  recognizing  the  presence  and  work  of 
iliis  beetle  and  its  broods  may  be  mentioned,  as  follows: 

PITCH   TUBES. 

The  tubes  or  halls  of  pitch,  which  arc  pushed  out  from  the  wounds 
made  by  the  beetles  when  excavating  an  entrance  for  their  galleries 
constitute  one  of  the  first  and  most  characteristic  indications  of  the 
presence  oi  this  pest  in  the  living  spruce.  If  upon  cutting  into  the 
bark  around  one  of  these  pitch  tubes,  injuries  are  found  like  those 
just  described  (Pis.  Ill  and  IV),  one  may  be  quite  certain  that  they 
arc  the  work  of  the  true  spruce  destroyer. 

APPEARANCE   OF    THE    LEAVES. 

The  leaves  of  a  dying  tree  infested  by  this  insect  change  from  the 
dark  healthy  to  a  pale  or  grayish  green,  and  soon  fall,  thus  indicat- 
ing the  presence  <>f"  this  pest.  And  if  the  bark  of  an  infested  tree  is 
examined  at  this  stage,  fully  developed  larval  and  even  fully 
developed  broods  of  the  adult  may  usually  be  found. 

APPEARANCE   OF    THE    TWIGS. 

Alter  the  leaves  have  fallen  the  infested  trees  present,  by  their 
reddish  appearance,  a  far  more  striking  contrast  with  the  healthy 
foliage,  and  are  thus  easily  recognized  at  a  considerable  distance.  If 
the  bark  is  examined  at  this  stage  the  broods  of  the  spruce  destroyer 
will  be  found  nearly  or  quite  fully  developed,  or  they  may  have 
emerged. 

APPEARANCE    OF   THE    BARK    AND    WOOD. 

Since  it  is  absolutely  necessary  for  the  beetle  to  deposit  its  eggs  in 
living  or  partly  living  bark,  in  order  for  the  3Toung  larva-  to  have  the 
proper  conditions  for  their  future  development,  there  is  seldom  more 
than  one  set  of  broods  developed  in  the  same  tree,  unless,  as  is  some- 
times the  case,  but  one  side  of  the  tree  is  attacked  one  year  and  the 
other  side  the  next,  when  two  sets  of  broods  might  develop  in  the 
same  tree.  As  a  rule,  all  have  emerged  before  the  twigs  begin  to 
change  from  their  fresh  reddish  appearance  after  the  leaves  have 

fallen.  After  this  Stage  is  passed  the  previous  presence  of  the  beetle 
i>  indicated  only  by  1  he  evidences  of  its  work  in  and  beneath  the  bark 
and  on  the  surface  of  the  wood,  which  may  be  readily  recognized  from 
the  illustrations  and  descriptions  given.  (PI.  V.)  The  pitch  tubes 
sometimes  remain  on  the  bark  several  years  after  the  tree  dies,  ami 

as  long  as  there  is  any  bark  on  the   middle    portion  of  the   trunk    this 


23 

evidence  will  enable  anyone  who  has  given  the  subject  some  atten- 
tion to  determine  that  such  trees  were  attacked  while  living. 

After  all  of  the  bark  has  fallen  from  the  trunk  of  standing  or  felled 
trees,  the  characteristic  grooves  in  the  surface  of  the  wood,  made  b}T 
the  beetle  when  the  primary  galleries  were  excavated,  are  often  quite 
conspicuous,  even  on  trees  that  have  been  dead  for  fifteen  to  twenty 
years. 

WOODPECKER    WORK. 

Another,  and  indeed  one  of  the  most  conspicuous  evidences  of 
the  presence  of  the  spruce-destroying  beetle,  is  found  in  the  work 
of  woodpeckers  on  the  middle  trunk  of  the  dying  and  dead  trees. 
Scarcely  an  infested  tree  escapes  the  bird,  and  the  outer  bark  removed 
by  them  in  their  search  for  the  insect  gives  such  trees  at  first  a  red, 
and  later  a  smooth,  light-grayish  appearance,  which  is  very  conspicu- 
ous. Even  living  trees  infested  by  the  insect  can  be  recognized  by 
this  means  at  a  greater  distance  in  the  woods  than  by  any  other  of 
the  conditions  mentioned.  It  must  be  remembered,  however,  that  all 
spruce  trees  showing  the  work  of  woodpeckers  are  not  necessarily 
infested  by  the  spruce  destroyer.  For,  as  in  the  case  of  trees  which 
have  been  infested  with  other  bark  beetles,  or  the  flat-headed  and 
round-headed  borers,  the  birds  scale  off  the  bark  in  the  same  or  a  similar 
manner.  Examples,  however,  of  trees  dying  from  the  work  of  these 
secondary  enemies  are  rarely  met  with.  Therefore  the  work  of  the 
woodpeckers,  especially  in  the  Maine  woods,  is  quite  reliable  evidence 
of  the  presence  of  the  spruce  destroyer. 

A  COMMON  FUNGUS  ON  THE  BARK  OF  DEAD  TREES. 

Nearly  all  recently  dead  trees,  and  even  some  that  are  not  yet 
dead  but  contain  broods  of  the  beetle,  are  found  to  have  a  small, 
yellow,  globular  fungus  (PI.  VI)  protruding  either  from  the  holes  in 
the  roof  of  the  egg  galleries  or  those  made  when  the  adults  emerged 
from  the  bark.  This  fungus,  which  grows  beneath  the  bark,  pushes 
its  way  out  to  develop  spores  or  fruiting  parts. 

These  fungi  are  conspicuous  objects,  and  they  often  occur  by  hun- 
dreds on  the  bark  of  the  trees  for  two  or  three  years  after  they  have 
died  and  the  beetles  have  emerged.  The  fact  that  the  work  of  the 
spruce-destroying  beetle  seems  to  make  the  conditions  more  favorable 
for  the  introduction  and  subsequent  growth  of  this  fungus  indicates 
that  it  is  more  closely  associated  with  the  work  of  this  beetle  than  is 
any  of  the  other  bark  and  wood-infesting  fungi  of  the  spruce.  It 
therefore  serves  as  good  external  evidence  that  the  dead  trees  on 
which  it  is  found  were  killed  by  the  beetle.  It  will,  however,  grow 
from  the  burrows  made  by  other  insects  in  the  bark,  or,  as  observed 
in  one  instance,  from  the  burrows  of  wood-mining  beetles,  Xyloterus 
biviitaius  Kirby,  in  wood  from  which  the  bark  had  been  removed. 


24 

THE    PRINCIPAL   NATURAL    ENEMIES   OP  THE   SPRUCE-DESTROYING 

BEETLE. 

Among  a  number  of  insecl  enemies  of  the  different  stages  of  the 
beetle  al  Least  two  are  worthy  of  special  mention— one  a  true  parasite, 
the  other  a  predaceous  enemy. 

\    PARASITIC    INSECT. 

The  commonest  parasite  of  the  larvaj  is  a  small  four-winged  wasp- 
like inscci  belonging  to  the  order  Hymenoptera,  family  Braoonidae, 
genus  Bracon,  and  species  simplex  Cress.  This  insect  appears  on  the 
wing  about  the  time  or  a  little  before  the  beetles  emerge  from  the  bark 
in  the  early  summer  and  commences  to  deposit  its  eggs  by  means  of  a 
long,  stinglike  ovipositor  which  it  inserts  in  and  through  the  bark 
infested  by  different  stages  of  the  larva?,  on  or  by  which  it  places  its 
eggs.  'The  minute  maggot  hatching  from  this  egg  attaches  itself  to 
the  side  of  its  victim  and  sucks  out  and  feeds  upon  the  liquids  of  its 
body.  The  beetle  larva  soon  dies,  and  after  the  parasite  larva  has 
attained  its  full  growth  as  such  it  incases  itself  in  a  thin,  paperlike 
cocoon  (PL  VII)  in  which  it  goes  through  its  transformation  to  the 
adult.  It  then  emerges  and  in  a  like  manner  continues  its  good  work 
in  destroying  the  destroyer.  While  cocoons  of*  this  parasite  were  fre- 
quently met  with  in  the  larval  mines  of  the  beetle  in  nearly  every 
locality  where  infested  trees  were  examined,  it  was  nowhere  common 
enough  to  be  of  any  special  service  except  near  the  sources  of  the 
Kennebago  and  Dead  rivers.  Here  it  was  quite  common  and  had 
killed  a  great  many  Larvae.  In  one  tree  as  many  as  six  cocoons  were 
found  in  a  piece  of  bark  2  inches  square;  It  is  only  in  the  thinnest 
bark,  however,  that  this  parasite  can  do  much  good  in  destroying  the 
larva*,  and  since  the  beetles  usually  select  only  the  old  trees  with  thick 
bark,  and  do  not  infest  the  tops  where1  the  bark  is  thinner,  it  would 
appear  that  this  parasite  can  not,  alone,  do  a  great  amount  of  good. 
In  connection  with  other  beneficial  factors,  however,  it  contributes  its 
share  to  reducing  the  numbers  of  the  destructive  beetles,  and  thus  is 
an  important  factor. 

A   PREDACEOUS   BEETLE. 

Different  stages  of  a  beetle  closely  related  to  the  one  that  was  intro- 
duced by  the  writer  into  the  spruce  and  pine  forests  of  West  Virginia 
from  Germany  in  1892-93,  to  prey  Upon  the  destructive  pine  bark 
beetles,  were  frequently  met  with  when  examining  infested  trees,  but 
were  not  especially  common,  except  in  t he  same  section  where  the  par- 
asite was  common. 

This  beetle  belongs  to  the  order  Coleoptora,  family  CleridaB,  genus 
Thanasimus,  and  species  niibUus,  It  is  antlike  in  appearance,  espe- 
cially when  running  about  on  the  bark.     The  adult  is  about  one-fourth 


25 

of  an  inch  long  and  one-sixteenth  broad.  Its  head  is  black;  middle 
portion  of  the  body  red;  the  wing  covers  are  marked  with  zigzag  black 
and  gray  transverse  bands. 

The  adult  emerges  from  the  bark  of  the  infested  tree  somewhat 
earlier  than  the  spruce-destroying  beetle,  and  remains  hidden  under 
the  flakes  of  bark  or  in  the  moss  until  the  adults  of  the  spruce  beetle 
commence  to  emerge.  It  then  pounces  upon  the  beetles  as  they 
emerge  and  devours  them.  When  those  that  escape  fly  away  to  settle 
on  the  living  trees,  this  little  clerid  enemy  evidently  does  as  other 
clerid  species  do.  It  accompanies  them  and  continues  its  work  until 
the  escaping  beetles  have  burrowed  into  the  bark.  The  adult  clerid 
does  not  follow  them  into  their  galleries,  but  does  the  next  best  thing — 
deposits  its  eggs  at  the  entrances,  so  that  the  active  reddish  worms 
hatching  therefrom  can  find  their  way  into  the  bark  and  feed  on  the 
bark-beetle  larva?. 

When  the  clerid  larvae  attain  their  full  size  the}'  retire  from  the 
larval  mines  they  have  depopulated  and  enter  the  central  tube  in  the 
primary  or  egg  gallery  made  by  the  spruce  beetle.  This,  in  fact,  seems 
to  be  a  favorite  place  for  them  to  make  their  pupa  cases  in  which  to 
transform  to  the  pupa  and  adult.  Some  of  the  larva1  evidently  make 
pupa  cases  in  the  outer  bark,  as  is  the  common  habit  of  nearly  all  the 
otlier  species  known  to  the  writer;  but  it  would  seem  that  by  far  the 
greater  number  pupate  within  the  central  tube  in  the  broad  egg  gal- 
leries excavated  by  the  bark  beetle. 

This  clerid  is,  without  doubt,  a  very  efficient  enemy  of  the  bark 
beetle,  especially  when  it  occurs  in  such  numbers  as  observed  in  the 
spruce  near  the  head  of  the  Kennebago  River. 

A  parasite  was  reared  from  a  pupa  case  of  this  clerid  which  is  very 
closely  allied  to  a  parasite  of  the  imported  clerid  found  by  the  writer 
in  Germany. 

BIRDS   AS   ENEMIES    OF    THE    BEETLE. 

As  has  already  been  stated,  woodpeckers  are  the  most  important 
enemies  of  the  bark  beetle,  and  appear  to  be  of  inestimable  value  to 
the  spruce-timber  interests  of  the  Northeast.  Indeed,  I  feel  confi- 
dent that  in  the  many  hundreds  of  infested  trees  examined  at  least 
one-half  of  the  beetles  and  their  young  had  been  destroyed  by  the 
birds,  and  in  many  cases  it  was  evident  that  even  a  greater  propor- 
tion had  perished  from  this  cause  alone. 

Estimating  100  beetles  to  the  square  foot  of  bark  in  the  average 
infested  tree,  and  an  average  of  60  square  feet  of  infested  bark,  it  is 
possible  for  each  tree  to  yield  an  average  of  6,000  individuals;  one 
hundred  trees,  600,000,  and  so  on.  It  is  therefore  plain  that,  if  one- 
half  or  two-thirds  of  this  number  are  destroyed  by  the  birds  and  other 
enemies,  the  amount  of  timber  the  remainder  can  kill  will  be  lessened. 
This  is  all  the  more  apparent  when  it  is  remembered   that  it   is  only 


2fi 

when  the  beetles  oocuriii  great  numbers  that  they  can  overcome  the 
resistance  of  i  In*  Living  trees. 

The  following  is  a  list  of  the  common  and  scientific  names  of  the 
woodpeckers  of  northern  New  England,  kindly  prepared  forme  by 
Dr.  C.  Ilari  Merriam,  Chief  of  the  Biological  Survey,  U.  S.  Depart- 
menl  <>r  Agriculture: 

Hairy  woodpecker .... Dryobatex  villosus. 

I  )< >\vn v  woodpecker Dryobates pubescent  medianus. 

Arctic  three-toed  woodpecker. Picoides  arcticus. 

1  landed  three-toed  woodpecker . Picoide*  americanus. 

Yellow-bellied  woodpecker  . l.Sphyrapicus  varius. 

Red -headed  woodpecker Melanerpes  erythrocephalus. 

Flicker.   . . .   Colaptes  auratus  luteus. 

Pileated  woodpecker Ceophloeus  pileatus  abietorum. 

No  positive  evidence  was  obtained  as  to  which  one  or  more  of  these 
hi  ids  is  to  be  credited  with  the  larger  part  of  the  beneficial  work, 
but,  from  such  observations  as  were  made  in  the  woods  and  informa- 
tion given  by  Dr.  Merriam,  and  through  one  of  his  correspondents, 
Mr.  William  Brewster,  at  Bethel,  Me.,  it  would  appear  that  the  Arctic 
three-toed  and  handed  three-toed  woodpeckers  render  by  far  the 
greatest  service,  and  probably  do  their  principal  feeding  during  the 
winter  on  the  species  of  insect  now  under  consideration. 

A   FUNGOUS   DISEASE  OF   THE   BEETLE. 

While  quite  a  number  of  beetles  and  larva3  were  found  which  had 
evidently  perished  from  a  fungous  disease,  the  percentage  dying  from 
this  cause  was  not  sufficient  to  be  of  any  perceptible  benefit. 

CLIMATIC    CONDITIONS. 

While  very  severe  freezing,  or  a  sudden  change  from  cold  to  warm, 
or  vice  versa,  may  kill  a  great  many  of  the  pupas,  young  beetles,  and 
even  the  larva',  except  in  a  few  cases  but  little  evidence  was  found 
showing  thai  these  conditions  had  produced  appreciable  effects. 

THE    PRINCIPAL   INSECT    ALLIES   OF   THE    SPRUCE-DESTROYING 

BEETLE. 

Among  the  large  number  of  different  kinds  of  insects  which  come 
ti>  the  aid  of  the  spruce-destroying  beetle,  or  follow  its  attacks, 
there  are  at  least  two  which  are  worthy  of  especial  mention  in  this 
connection;  one  is  the  spruce  Polygraphus,1  or  lesser  spruce  hark 
beetle,  while  the  other  is  the  spruce  Tetropium.8 

THE   SPRUCE    POLYGRAPHUS. 

This  is  by  far  the  commonest  secondary  enemy  of  the  spruce 
throughout  the  spruce  region  of  West  Virginia,  and  was  found  to  he 
exceedingly  common  in  all  of  the  sections  visited   in   northwestern 

Polygraph***  rufipennis  Kirhy.  Tetropium  cinnamopterutn  Kir  by. 


27 

Maine.  It  belongs  to  the  same  family  of  beetles  as  the  true  destroyer, 
but  to  an  entirely  different  genus.  The  specific  name,  rufipennis, 
given  to  it  by  Kirby,  is  unfortunately  the  same  as  that  lie  gave  to  the 
Dendroctonus  described  from  the  same  region.  This  has  caused 
much  confusion  in  the  writings  of  entomologists  and  others  relating 
to  the  insect  enemies  of  the  spruce. 

This  species  is  enormously  abundant  in  all  injured  and  dying  stand- 
ing trees,  and  in  the  bark  of  the  branches,  tops,  and  stumps,  in 
cuttings,  windfalls,  etc.  (PI.  VIII,  e,  and  PI.  IX.)  Its  abundance, 
together  with  its  habit  of  infesting  the  tops  of  trees  immediately  after 
the  middle  portion  of  the  trunk  or  base  has  been  attacked  by  the 
spruce-destroying  beetles,  renders  it  one  of  the  most  efficient  allies 
of  the  primary  enemy. 

The  adult  is  a  small  black  beetle  about  .08  of  an  inch  long  and  .01 
of  an  inch  broad.  It  is  easily  distinguished  from  all  other  spruce 
bark  beetles  of  similar  size  and  form  by  the  fact  that  each  of  its  com- 
pound eyes  is  divided  by  a  smooth  narrow  space.  It  passes  the  win- 
ter in  all  stages  within  the  bark  of  spruce  stumps,  logs,  and  the  tops 
of  felled  and  standing  trees.1 

THE    SPRUCE   TETROPIUM. 

This  is  the  round-headed  bark  and  wood-miner  which  was  found  to 
be  so  common  in  the  spruce  of  West  Virginia  in  1891,  where  its  work 
contributed  to  the  rapid  decay  of  the  wood  of  dead  trees.2  It  is  very 
common  in  the  spruce  of  Maine,  where  it  was  observed  by  the  author 
in  the  stumps  and  logs  of  recently  felled  trees  and  toward  the  base 
of  trees  attacked  by  the  spruce  destroyer.  Indeed,  an  attack  by  the 
latter  is  followed  almost  immediately  by  the  Tetropium  adult,  which 
deposits  its  eggs  in  the  outer  bark  from  toward  the  middle  of  the 
trunk  to  the  base.  The  young  larva?  are  capable  of  mining  through 
the  living  bark  (PI.  X)  and  continuing  their  work  regardless  of  the 
sap  and  pitch.  Therefore,  this  insect  must  be  classed  as  one  of  the 
principal  aids  to  the  spruce  beetle  in  not  only  causing  the  death  of 
the  trees,  but  in  contributing  to  the  rapid  decay  of  the  wood. 

OTHER   INSECTS. 

Numerous  other  insects  which  aid  in  causing  the  death  and  decay 
of  spruce  might  be  mentioned  (Pis.  VIII,  XI,  and  XII),  but  the  two 
just  referred  to  are  by  far  the  most  important.  There  may,  how- 
ever, be  an  exception  in  the  defoliating  insects  (PI.  XIII),  which,  it 
is  believed,  may  contribute  great!}'  to  produce  favorable  conditions 
for  the  attack  of  the  spruce-destroying  beetle. 

1  For  a  more  detailed  account  of  this  beetle  see  Bulletin  56,  W.  Va.  Agricultural 
Experiment  Station.  "  Report  on  Investigations  to  Determine  the  Cause  of 
Unhealthy  Conditions  of  the  Spruce  and  Pine,  from  1880  to  180;],''  pp.  246-251. 

-  Ibid.,  pp.  239-242,  259,  438. 


2S 

HISTORICAL   REFERENCES. 

In  the  following  paragraphs  attention  is  called  to  a  number  of  early 
references  i<>  tin*  <l<iai  h  of  spruce  in  the  forests  from  New  York  to  New 
Brunswick,  probably  caused  by  the  spruce-destroying  beetle: 

1818.  The  earliest  reference  to  dying  spruce  in  the  Northeast  is 
probably  that  contained  in  a  Idler  from  Hon.  R.  II.  Gardner  to  Mr. 
A.  G.  Tenney,  editor  of  t  he  Brunswick,  Me.,  Telegraph,  and  quoted  by 
Packard.1  Mr.  Gardner  stated  that  "he  had  often  heard  his  father 
speak  of  a  great  destruction  of  timber  east  of  the  Penobscot  in  1818." 
Dr.  Packard  also  states2  thai  he  was  informed  by  Mr.  E.  A.  Coe,  who 
got  his  informal  ion  from  General  Smith,  of  Norridgewock,  that  "the 
spruce  growth  about  that  town  and  Waterville  early  in  this  century 
had  been  diseased  and  died  very  much  as  in  the  past  few  years." 

1881-82. — Another  early  record  of  dying  spruce  is  that  obtained  by 
Mr.  Hough  from  a  correspondent,  Hon.  Daniel  W.  Taylor,  of  Sher- 
burne, Yl. ; 

181/0. — About  the  year  L880  Hough  '  was  informed  by  a  correspond- 
ent in  Newport,  Sullivan  County,  X.  II..  "that  some  forty  years  ago 
the  mortality  of  the  spruce  timber  was  xvvy  great  on  the  hills  and 
mountains  in  that  part  of  the  State     *     *     *." 

1844-1859. — When  Professor  Peek  made  his  investigations  of  the 
dying  spruce  in  the  Adirondack^,  in  1874, 5  he  learned  that  the  spruce 
had  been  dying  for  about  fifteen  years  in  Lewis  County  and  that  in 
Rensselaer  County  the  same  destruction  had  been  observed  about 
thirty  years  ago. 

1850. — About  L850  the  spruce  was  said  to  have  turned  red  and  died 
on  about  500  acres  at  Irasburg,  Yt.,  which  was  supposed  to  have  been 
caused  by  worms.'' 

1871-1880 — Between  1871  and  L 880 great  destruction  occurred  in  the 
spruce  from  New  York  to  New  Brunswick.  Hough  in  L8827  quoted 
information  from  a  correspondent  in  Colton,  St.  Lawrence  County, 
N.  Y.,  who  says  of  a  journey  made  in  August,   L880: 

After  getting  about  40  miles  up  the  river  we  began  to  come  into  a  region  where 
a  large  part  of  the  spruce  was  dead  and  at  least  half  of  it  had  lost  its  value.  From 
Mich  inquiries  as  could  be  made  we  learned  that  large  portions  of  this  timber  were 
destroyed,  including  the  best  qualities  and  trees  of  the  largest  size.  These  inju- 
ries had  1  een  going  on  about  ten  years  and  were  still  in  progress.  The  yield  of 
these  timber  lands  was  about  (J, 000  standard  of  10-inch  logs  to  the  s  lUare  mile. 


Fifth  Report  U.  S.  Ent.  Com.,  p.  817. 
Had.,  p.  820. 

Eteporl  on  Forestry.  1882,  p.  282. 
•Ibid.,  p.  262. 

Proc.  Albany  Inst..  Vol.  II.  1876,  pp.  2$M  301;  also  Twenty-eighth  Report  New 
V<.rk  State  Museum.  1878,  pp.  82  88. 
'Information  from  J,  E.  Jamson,  Report  on  Forestry,  1882,  pp.  262  263. 
Reporl  on  Forestry,  1882,  p.  268;  see,  also,  Twenty-eighth  and  Thirtieth  Reports 
New  fork  State  Museum  for  much  addil  onal  information  by  l>r.  Peck. 


S9-1884. — In  1884  Dr.  Packard  was  informed1  that  in  the  vicinity 
of  Beed's  Hotel,  Keene  Flats,  in  tlie  Adirondack^,  the  spruce  had  been 
dying  for  tlie  past  fifteen  years. 

1874-1881. — In  the  Home  and  Farm,   of  Brunswick.   Me..  July  14, 

1881,  Mr,  A.  G.  Tenney  states,  as  quoted  by  Packard,2  that  he  had 
been  informed  by  an  intelligent  and  experienced  lumberman  of  North 
Somerset  County.  Me.,  that  the  first  appearance  of  the  insect  (that 
killed  the  trees)  was  in  1S74.  and  up  to  1881  it  was  on  the  increase. 

1876-1881. — Hough  3  states  that  great  destruction  (estimated  by  Mr. 
Robert  Conners  to  be  1,000,000,000  feet)  of  spruce  occurred  on  tlie 
Allegash  and  other  tributaries  of  the  St.  John  River  in  northern 
Maine  and  that  these  injuries  extended  through  the  spruce  forests  of 
the  whole  of  Aroostook  County  and  the  most  northern  range  of  towns 
in  Somerset  and  Piscataquis  counties  adjoining. 

1876. — Hough4  states  that  about  the  year  1875  the  spruce  timber  in 
New  Brunswick  along  the  Mivamichi  River  began  to  die  off  in  great 
abundance,  the  hills  suffering  more  than  the  valleys,  and  the  dense 
woods  more  than  those  where  partial  clearings  had  been  made.  The 
largest  and  best  of  the  timber  suffered  most,  and  the  young  growth 
appeared  somewhat  favored,  but  was  not  wholly  exempt. 

1870-1873,  I88O-I880.— In  1900,  Mr.  Cary  states,  in  the  Forester,  of 
March,  page  52,  that — 

Old  lumbermen  tell  of  a  great  loss  of  spruce  timber  iu  northern  Vermont  and 
New  Hampshire,  extending  into  neighboring  lands  in  Canada,  which  occurred 
some  thirty  years  ago.  The  drives  of  the  Connecticut  River  are  said  to  have 
been  made  up  for  some  years  thereafter  largely  of  dead  timber.  The  same  region 
suffered  again  between  ten  and  fifteen  years  ago. 

In  Maine,  beginning  about  fifteen  years  ago.  a  township  on  the  Androscoggin, 
which  at  the  time  was  called  the  best  spruce  land  on  the  river,  had  a  large  part 
of  its  value  destroyed  in  the  course  of  three  or  four  years.  On  the  Allegash 
River,  in  northern  Maine,  there  are  several  adjoining  townships  which,  about 

1882.  were  greatly  damaged.  In  some  places  90  per  cent  of  the  spruce  is  said  to 
have  been  killed:  in  fact,  all  of  the  grown  timber. 

1897. — In  August.  1897,  Fisk"  found  the  spruce  dying  and  infested 
with  the  beetles  in  northern  New  Hampshire. 

Different  authors  and  their  correspondents  estimate  that  10,  50,  and 
as  much  90  per  cent  of  the  matured  timber  had  died  over  large  areas. 

Different  authors  and  correspondents  have  estimated  that  the  tim- 
ber was  of  little  value  after  the  second  year,  and  many  claim  that 
it  is  worthless  after  the  second  or  third  year.  Mr.  Cary  thought f' 
that  there  was  a  lessening  of  something  like  50  per  cent  in  available 
timber  within  two  years. 


1  Fifth  Report  of  U.  S.  Ent.  Com.,  p.  818. 
Ibid.,  p.  813. 

Report  on  Forestry.  1882,  p.  259. 
Ibid.,  p.  259. 

5 Bulletin  17,  new  series.  Division  of  Ent..  U.  S.  Dept.  of  Agr..  pp.  67-769, 
The  Forester,  March,  1900,  p.  53. 


30 

Probably  1 1 1 « *  first  mention  of  an  attempt  to  utilize  the  dying  and 
dead  timber  was  l>y  Professor  Peck,1  which  is  as  follows: 

A  lumber  firm  found  that  their  spruce  timl>er  was  rapidly  dying  about  1840-1845, 
and  to  make  their  losses  as  light  as  possible  they  made  haste  to  open  roads  in  the 
forest,  that  they  might  draw  out  and  work  up  as  many  dead  spruce  as  practicable 
before  decay  should  render  them  entirely  worthless:  but  with  all  of  their  prompt- 
D68fl  they  suffered  no  inconsiderable  loss,  for  these  dead  trees  soon  became  too 
much  decayed  to  make  marketable  lumber. 

The  next  mention  of  attempts  to  save  the  dead  timber  was  by 
Hongh,'who  referred  to  a  statement  in  the  National  Economist  of 
Ottawa,  Canada,  that  "one  operator  in  New  Krnnswick  will  cut 
50,000,000  feel  of  spruce  (in  1881)  because  of  the  damage  done  by 
insects,  and  to  save  it  from  total  loss." 

Packard8  was  informed  by  a  lumberman  that  the  owners  of  the 
dying  spruce  <»n  the  St.  Croix  were  advised  in  about  1875  to  fell  and 
utilize  ii . 

REMEDIES  AND  METHODS  OF  PREVENTION. 
REVIEW    OF   PROPOSED   METHODS. 

In  addition  to  the  published  references  to  remedies  and  methods  of 
preventing  loss  already  quoted,  the  following  should  be  mentioned  in 
this  connection,  in  order  to  call  attention  to  the  practical  and  imprac- 
i  Leal  feat  ures  of  some  of  them : 

Professor  Peck  '  suggests  the  protection  of  woodpeckers,  which,  as 
subsequent  observations  by  Hough,  Cary,  and  the  writer  show,  is  a 
recommendation  of  considerable  importance. 

STRIPPING    OFF    AND    BURNING    THE    BARK. 

Peck,6  Hough,6  and  Packard7  all  recommend  cutting  the  dead  trees 
and  stripping  off  the  bark  and  burning  it  to  destroy  the  insect;  but 
Peck  and  Hough  expressed  some  doubt  as  to  its  practicability  in  this 
country.  This  old  remedy  against  insect  enemies  of  forest  and  other 
trees  has  been  so  often  recommended  in  this  and  other  countries  that 
it  is  becoming  stereotyped,  but  unless  it  is  positively  known  whether 
or  not  the  conditions  are  favorable,  necessary,  or  even  possible  for  its 
practical  application,  it  should  not  be  recommended  or  attempted. 

As  applied  to  the  spruce-destroying  beetle,  this  remedy  would  seem 
to  be  impracticable  in  the  extreme.  Indeed  it  would  be  in  our  Amer- 
ican forests  unsafe  under  ordinary  conditions  to  attempt  to  burn  the 
bark  in  summer  on  account  of  the  danger  of  starting  forest  tires.  If, 
on  the  other  hand,  as  is  the  case  in  the  .Maine  woods,  the  peeling  of 
the  Logs  is  adopted  as  a  business  policy  in  the  regular  logging  opera- 


Proc.  Alb.  Inst..  1876,  Vol.  Ill,  p.  295,  and  Twenty-eighth  Rep.,  pp.  32-88. 

Report  on  Forestry,  1882,  p.  259. 
'  Fifth  Report,  V.  S.  Ent.  Com.,  p.  819. 
•Proc.  Alb.  Inst.,  Vol.  Ill,  p.  399;  also  38th  Report,  p.  86. 

88th  Report, pp.  86,87.  'Report  of  1877. 

5th  Report,  U.S.  Ent.  Oom.,  p.833. 


31 

tions,  then  the  removal  of  the  bark  from  infested  trees  in  and  accessi- 
ble to  the  regular  summer  cuttings  at  a  time  when  it  Is  tilled  with  the 
young  stages  of  the  insect   is  practicable,  and  may  alone,  with  little 

additional  expense,  contribute  greatly  to  the  reduction  of  the  pest. 
In  no  ease,  however,  would  it  be  necessary  to  burn  the  bark,  either  in 
summer  or  winter.  The  greater  number,  if  not  all,  of  the  insects 
would  perish  from  the  drying  of  the  bark  in  the  summer,  freezing  in 
winter,  and  from  the  attaek  of  birds  and  other  enemies.  It  is  true 
that  some  of  the  adults  may  escape  in  the  summer  to  attaek  other  trees, 
but  it  is  believed  that  little  trouble  would  result  from  this  source. 

DESTRUCTION    OF    DEAD    TREES. 

This  is  another  method  which  is  often  recommended  for  the  pre- 
vention of  depredation  by  insect  enemies  of  forests,  meaning  in  many 
cases  trees  which  have  been  dead  a  long  time,  as  well  as  stumps  and 
logs  in  which  it  is  supposed  destructive  insects  breed.  As  applied  to 
insect  enemies  of  living  trees,  or  those  which  make  the  primary  attack 
in  living  bark,  the  destruction  of  old  dead  trees,  stumps,  and  logs 
would  be  worse  than  useless,  since  all  of  the  really  dangerous  ene- 
mies emerge  from  the  trees  either  before  they  are  entirely  dead  or 
within  one  year  after  they  die.  The  only  apparent  advantage  to  be 
gained  as  applied  to  the  spruce  would  be  the  destruction  of  a  few  of  the 
insect  depredators  on  the  wood  of  dead  trees,  and  in  this  it  would  be  the 
most  exceptional  cases  where  there  would  be  any  appreciable  benefit. 

GIRDLING   TREES. 

This  is  an  old  method  practiced  in  Europe  and  quite  extensively 
recommended,  but,  like  most  other  methods,  it  is  only  applicable  to 
certain  kinds  of  insects  and  depends  on  specially  favorable  conditions 
for  its  desired  effect. 

INVESTIGATION    OF   THE    GIRDLED-TREE    METHOD. 

Some  evidence  found  in  the  felled  and  diseased  standing  trees  on 
the  first  and  second  days  of  the  investigation,  in  the  vicinity  of 
Wight's  camps,  suggested  to  the  writer  the  importance  of  experi- 
ments to  determine  the  relation  of  girdled  trees  to  the  attraction  of 
the  insects  away  from  the  living;  therefore,  the  girdling  of  large 
spruce  at  different  dates  during  the  summer  was  recommended  to 
Mr.  Cary  as  an  important  line  of  work  for  him  to  undertake. 

HACK-GIRDLED   AND   PEELED    SPRUCE. 

This  subject  was  kept  in  mind  throughout  the  investigation,  and 
some  good  opportunities  were  had  at  different  places  to  study  the  infiu- 
ence  of  the  common  practice  of  sportsmen,  loggers,  and  surveyors — 
hack-girdling  and  peeling  spruce  to  obtain  the  bark  for  camp  covering. 

In  the  VxCinity  of  Lincoln  Pond  large  numbers  of  peeled  spruce 
were  examined  on  May  30.  The  larger  number  of  these  had  been 
peeled,  as  we  were  informed  by  the  loggers,  in  July,  1808,  and  had 


32 

evidently  died  in  the  summer  of  L899.  At  the  lime  of  our  examina- 
tion the  bark  was  round  to  be  infested  with  great  numbers  of  Poly- 
graphia, principally  adults,  also  by  round-headed  and  flat-headed 
bark  and  wood-boring  Larvte,  but  no  examples  of  the  spruce-destroying 
I  dendroctonus  were  found. 

The  othei  trees  peeled  in  June  or  July,  L899,  were,  al  tin-  time  of 
our  examination,  Living,  the  leaves  green,  and  the  hark  above  the 
peeled  portion  was  filled  with  sap.  The  bark  of  these  trees  was  not 
infested  by  insects  of  any  kind,  so  far  as  we  could  observe.  The 
peeled  trees  in  l>oth  lots  ranged  from  *  or  9  inches  to  possibly  18 
inches  in  diameter,  but  not  many  of  them  were  over  L2  inches. 

On  June  7  some  Large  spruce  were  examined  near  the  inlet  to  Par- 
mecheenee  Lake  which  had  been  girdled  and  peeled  in  about  L895. 
one  that  had  been  hack-girdled  near  the  base  and  again  about  6  feel 
above    bad    been    infested    with   Dendroctonus,  and  the  broods  had 


Pig 


-Trees  girdled  by  different  methods:  a,  Hack-girdled:  b,  girdled  to  heartwood: 
girdled  and  peeled:  d,  hack  and  belt-girdled. 


hack- 


developed  and  emerged.  The  trees  that  were  peeled,  however,  were 
not  attacked  by  Dendroctonus,  but  had  been  infested  by  great  num- 
bers of  round-headed  bark  and  wood  borers  of  the  genus  Tetropium. 
On  June  8  more  hack-girdled  and  peeled  spruce  were  examined 
near  Rump  Pond  Camp,  which  had  been  infested  with  Polygraphus 
and  other  insects,  but  not  with  Dendroctonus. 


REPORT   OH   GIRDLING   EXPERIMENTS    BY   MR.  A.USTLN   I'ARY. 

A  number  of  spruce  trees  were  girdled  on  May  29  and  June  L3  in 
the  vicinity  of  Wight's  cuttings  on  Twin  Brook;  on  June  6  near 
Eiamel's  Camp,  on  the  Little  Magalloway;  and  on  June  16  near  Big 
Island  Pond,  at  thesourceof  the  Kennebago  River.  Upon  the  writer's 
return  home,  written  instructions  were  sent  to  Mr.  Cary  regarding  the 
girdling  experiments  and  observations  desirable  for  him  to  make  on 
the  habits  and  life  history  <>("  the  beetle.  The  different  methods 
of   yn'fdling  recommended  are  indicated  in  fig.  2.     The  satisfactory 


33 

mariner  in  which  these  instructions  were   carried  out,   the  time  and 
labor  involved  in  the  work,  and  the  value  of  Mr.  Cary's  observations 

will  be  indicated  by  his  report. 
Mr.  Gary  commenced  these  experiments  May  29;  his  report  was 

submitted  October  6  and  10,  1900.      It  is  as  follows: 

Camp  in  the  Msabows,  Maine. 

October  6,  1900. 
Dear  Professor  Hopkins:  I  send  you  herewith  report  of  iny  observations  this 
season.     They  do  not  go  very  far  toward  solving  the  problems  suggested,  but  as 
to  Dendroctonus  it  seems  to  me  they  do  teach  considerable. 

Sincerely,  vours.  Austin  Gary. 


All  of  the  trees  girdled  are  of  Red  Spruce,  and  unless  otherwise  mentioned  were 
to  all  appearances  healthy. 

The  inferences  to  be  drawn  from  the  results  depend  considerably  on  surround- 
ings, the  lay  of  the  land,  and  the  relation  of  the  girdled  trees  to  infested  and 
healthy  ones.     I  will  therefore  g<oup  my  notes  according  to  localities. 

Group  I. 

Group  I  is  at  edge  of  Wights  cutting  of  winter  of  1899-1900  and  near  the  clump 
of  infe-ted  trees  examined  on  May  28  by  yourself  and  the  writer.  Unless  other- 
wise stated,  the  trees  were  hack- girdled  by  striving  an  ax  through  the  bark  and 
into  the  sapwood  around  the  trunk  3  to  -3  feet  above  the  base. 

Trees  girdled  on  May  .   . 

Tree  Xu.  2:  Diameter  28  inches:  examined  June  19.  July  9,  September  1.  and 
October  4:  not  attacked  by  Dendroctonus. :  A  few  Xyloterus-  entered  the  wood 
in  the  girdle. 

Tree  No.  3:  Diameter  12  inches:  girdled  by  A.  D.  H. ;  examined  on  June  19, 
July  9.  and  September  1:  not  attacked  by  Dendroctonus.  October  4.  seemed  to  be 
losing  leaves:  sapwood  at  girdle  and  for  a  foot  above  stained  bluish  one-half  inch 
deep. 

Trees  girdled  June  19. 

Tree  No.  24:  Diameter  13  inches.  July  10,  attacked  by  a  few  Xyloterus.  Octo- 
ber 4,  no  change. 

Tree  No.  2.1:  Diameter  18  inches.  July  10.  numerous  Xyloterus  entering  at  and 
near  girdle.     October  4,  no  change. 

These  four  trees  are  about  30  yards  from  infested  trees  and  about  75  yards  from 
the  clump  of  trees  first  examined  on  May  28. 

Tree  No.  26:  Diameter  20  inches:  30  yards  from  clump  of  infested  trees.  July 
9,  a  few  Xyloterus  entering  wood  at  girdle:  bark  infested  with  Dendroctonus, 
Polygraphus  especially  abundant  below  the  girdle:  a  few  Sierus  annectens  found 
below  girdle.  September  1,  Dendroctonus  larva?  were  observed.  October  4, 
recently  developed  beetles  and  a  few  Tetropium  larva^  occurred  in  the  bark,  with 
numerous  Xyloterus  in  the  wood:  the  bark  was  then  loose,  the  leaves  down,  and 
the  wood  turning  brown. 

Tree  No.  27:  Diameter,  15  inches:  40  feet  from  infested  trees.  July  9.  infested 
by  Dendroctonus  and  Xyloterus  in  girdle;  Dendroctonus  galler.es  up  to  3  inches 
long,  with  numerous  eggs.     September  1,  numerous  larva?  and  pupa-  of  Denuroc- 


1  Dendroctonus piceaperda  Hopk.         Polygraphus  rufipennis, Kirby-Hopkins. 
-  Xyloterus  bivittatus  Kirby. 

3506— No.  L's-.UI 3 


84 

tonus,  also  numerous  Polygraphus  in  bark,  the  sapwood  being  stained  one-half 
inch  deep.     <  >n  i  kJtober  I  the  bark  was  dry  all  around  and  the  leaves  falling.  Den- 
droctonus  Larva?,  pupa?,  and  recently  developed   beetles  being  common  above 
e  and  Polygraphs  more  numerous  below. 
Tre  Diameter,  16  inches    hollow  at  base  and  with  thin  crown ;  close  to 

July  '■».  not  attacked.     ( )etober  4.  two  Dendroctonus  galleries  close 
irdle,  but  no  eggs  or  larva?;  nol  attacked  by  Xyloterus  even  at  girdle. 
( >n  ,lni\  9  a  large  tree  standing  by  No.  2 7  was  found  to  be  attacked  by  large 
numbers  of   Dendroctonus,  and  by  October   1  was  dead  and  the  leaves  fallen. 
Another  tree  !s  inches  in  diameter  near  No.  28  was  lightly  attacked  by  Dendroc- 
s,  and   by  October  I  showed  numerous  short  galleries   but  no  eggs  or  larva?. 
<  in  October    I    it  was  noted  that  a   13  inch  spruce,  standing  between  two  large 
infestt  '1  trees  LO  feet  apart,  had  been  attacked  in  1899,  but  recovered,  and  was  not 
again  attacked  this  season.     On  July  9  numerous  trees  halfway  between  No.  -  G 
and  the  infested  trees,  as  well  as  one  large  tree  near  them,  were  not  attacked. 
On  dune  19  1  saw  n<>  signs  of  the  beetles  emerging  from  the  infestel  trees,  and  no 
near  by  were  brum  attacked.     I  found,  however,  not  far  away,  in  a  stump 
Of  a  tree  cut  last  winter,  four  Dendroctonus  galleries,  and  more  on  July  9,  with 
many  Xyloterus  entering  the  wood,  but  could  find  no  other  stumps  or  tops  of  felled 
ue«-  which  were  infested  with  the  Dendroctonus. 

Gteoi  p  II. 

This  group  is  on  Wight's  "tote"  road,  higher  up  the  mountain,  halfway  to 
Cupsuptic  divide,  and  in  the  vicinity  of  numerous  infested  trees  attacked  the 
summer  of  L899. 

Trees  girdled  May  ."■>. 

Tree  No.  4.  Diameter.  20  inches:  close  to  infested  tree.  June  19,  infested  by 
Dendro  tonus.  July  11.  abundantly  infested,  the  galleries  being  as  much  as  :) 
inches  long  and  containing  eggs:  Xyloterus  common,  entering  wood  at  girdle  and 
elsewhere.  September  1.  many  of  the  leaves  had  fallen,  and  recently  developed 
beetles,  pupa1,  and  large  la.  vse  were  found  in  the  bark,  with  no  trace  of  parasites. 
( October  1.  all  the  leaves  fallen:  numerous  nearly  matured  adults  of  Dendroctonus, 
with  few  larva   and  pupae. 

Tree  No.  5:  Diameter.  16  inches:  40  feet  to  nearest  infested  tree.  June  19, 
infested  by  Dendroctonus.  .Inly  11,  Xyloterus  in  the  wood  and  Dendroctonus  in 
the  bark,  but  apparently  not  in  great  numbers.  September  1,  Dendroctonus 
abundant,  with  pupa1  and  large  larva?;  majority  of  the  leaves  fallen.  October  4. 
leaves  nearly  all  down:  recently  developed  beetles  some  fully  matured,  also  large 
and  pupa?,  with  some  parasites  and  one  Tetropium  larva. 

Tire  No.  6:  Diameter,  15  inches:  belt  girdled  by  removing  a  belt  of  bark  H 
inches  wide;  located  50  feet  away  from  nearest  infested  tre.j.  June  19.  infested  by 
Dendroctonus.  July  1 1.  gaderies  :>  inches*  long,  with  eggs.  September  1.  major- 
ity of  leaves  fallen:  Dendroctonus  abundant  in  bark.  <  )ctober  4,  leaves  nearly  all 
down;  pupae,  matured  larva?,  and  recently  developed  beetles  of  Dendroctonus, 
with  a  few  parasites:  also  a  smaller  bar:-:  beetle  than  Dendroctonus. 

Tier   No.    7:    Diameter.   22   inches;  girdled    by  cutting   through   the  sapwood. 

June  19  and  July  11,  not  infested.     September  1,  mist  of  the  leaves  fallen  and  the 

.    i-  drying  without   staining:  a  few.  possibly  eight,  Dendroctonus  galleries 

observed,  but  very  short  and  without  eggs  or  larva?:  also  some  Polygraphias  and 

bropinm  larva  in  bark.    October  I.  Bame  condition;  wood  not  stained. 

ZVee*  girdled  ScpU  mber  /. 

Tree   No.   US:    Diameter,  18  inches,  a    few  rods  from  infested  trees.     October  4, 
nol  infested  and  in  normal  condition. 
Tree  No.  ii:  Diameter,  L3  inches.     October  I.  in  normal  condition. 


35 

Tree  No.  45:  Diameter.  13  inches:  near  infested  trees.  October  4,  in  .normal 
condition. 

Of  the  four  trees  girdled  here  May  29,  three  were  infested  by  Dendroctonus  June 
19,  this  being  the  first  new  work  of  the  season  observed.  Some  of  the  galleries 
were  then  2  inches  long.  They  had  numerous  eggs,  and  one  ventilation  hole  was 
observed  started,  but  not  through.  The  beetles  in  the  galleries  in  some  cases  were 
both  black,  and  in  others  both  bronze,  or  one  bronze  and  one  black. 

In  order  to  get  further  information  in  this  locality,  a  half  acre  was  laid  out  by 
.^uess,  which  included  all  the  girdled  trees  as  well  as  the  dead  ones  and  those 
infested  last  year.  Ail  of  the  trees  were  examined  and  their  local  relations  to  the 
probable  source  of  infestation  noted  on  June  19.  The  conditions  were  again 
stubed  on  October  4.  and  the  resu  ts  are  given  below.  Ail  trees  10  inches  or  less 
in  diameter  standing  on  the  halt  acre  are  omitted. 

Condition  of  tires,  ocer  10  inches  in  diameter,  on  one-half  acre  of  land. 


Condition  June  19. 


Condition  October  -t. 


Killed  in  1898  or  1899    

Killed  in  1899;  infested  with  Dendroctonus 

pupae,  etc . 

Killed  probably  in  1898 

Killed   in  1899,  infested  with  Dendroctonus 

pupae,  etc. 
Killed    in    1>9;»:     infested    with    pupa-    and 

Killed  probably  in  1898 .... 


IS 
Hi 

20 

13 

18 

SO 


13 


16 


16 


Killed  two  or  three  years  ago 

Attacked  last  year,  but  not  this:  leaves  green. 

but  wood  and  bark  drying. 
Hack-girdled:    attacked    by   Dendroctonus. 

(Tree  No.  i.  Group  II. » 
Two   roots   extending  into   road  damaged: 

attacked  by  Dendroctonus. 
Attacked  by  Dendroctonus 


Probably  infested  last  year  and  again  this: 

bark  dead  on  one  side. 
Girdled   through  sap  wood;    not    attacked. 

(TreeXo.  7.  Group  II.) 
Attacked   by  Dendroctonus  last   year:  not 

again  this:  strip  of  bark  and  wood  on  one 

side  dry;  top  green. 
Attacked  last  year:    infested    with   beetles 

and   pu  ia?:   no  fresh  infestation:  part  of 

wood  dry:  top  green:  Xyloterus  in  roots. 
Attacked  last  year,  but  no  work  of  larva; 

not  attacked  this  year. 
Belt-girdled:  attacked.     (Tree  No.  6,  Group 

II.) 
Hack-girdled:  attacked.   (Tree  No.  5,  Group 

II.) 
Hollow  at  base;     small  crown:     lightly  at- 
tacked. 
Attacked  this  year 


Not  infested 

....do 

....do 

....do 

...do.   

....do 

...  .do 

...do 

...  do.. 

....do 


Fine  thrifty  tree 

A  heavy-crowned  tree. 

Living 

Not  attacked 


Sapwood  brown  and  soft:  Polyporus  fungus 
on  bark. 

Sapwood  brown  and  soft 

Sapwood  brown,  streaked  and  softening.     A 

few  Polyporus  on  bark. 
Sapwood   on    one    side   rotten:    remainder 

brown  and  softening;  Polyporus  on  bark. 

Leaves  fallen:  wood  and  bark  dry. 

Leaves  all  fallen:  wood  and  bark  drying. 

Wood  dry:  leaves  falling. 

Majority  of    leaves    fallen:    wood    dry  and 

browning. 
All  dead:  leaves  fallen:  sapwood  browning. 

Wood  drying  without  stain:  8  Dendroctonus 

galleries  without  progeny. 
Not  attacked:  living    bark  covering   scars: 

leaves  still  green. 

Previous  y  dead  wood  decaying;  leaves  yel- 
low and  majority  fallen. 

Xot  attacked:  old  scars  healing. 

Dead:  leaves  nearly  all  fallen. 

Majority  of  leaves  down. 

Larva1   and   pupsB   of    Dendroctonus    abun- 
dant. 
Dying  all  around,   leaves  nearly  all  fallen; 
infested  by  Dendroctonus  andTetropium. 
Xot  infested. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Attacked  and  killed:  leaves  fallen;  strips  of 

wood  browning. 
Infested:  many  Dendroctonus  galleries,  but 

no  eggs  nor  larva?:  leaves  not  fallen. 
Abundantly     infested     by     Dendroctonus,  ' 

mainly  in  pupa  stage:  leaves  not  fallen. 
Abundantly  infested;  bark  dry  all  around; 

leaves  not  fallen. 
Xot  attacked. 


36 

Three  of  the  four  trees  girdled  on  May  29  were  infested  by  large  numbers  of 
Dendroctonus  on  June  m,  but  there  were  many  other  apparently  healthy  trees 
which  were  also  attacked.  At  this  date  no  newly  infested  trees  were  noticed  that 
more  than  ~><»  Feet  away  from  the  source  of  infection.  Later  the  infestation 
ded  farther,  but  still  it  appeared  that  the  trouble  spread  but  slightly  beyond 
the  limits  of  the  half  sere.  Among  the  trees  lightly  attacked  in  1809  only  1  was 
reattacked  and  killed  this  year.  Indeed,  it  seems  that  if  a  tree  recovers  from  the 
first  attack  i!  usuall\  escapes  the  next  year.  Numerous  examples  of  this  have  been 
observed. 

()l  the  84  trees  noted  on  the  one-half  acre,  7  had  been  dead  from  one  to  three 
-  I  angirdled  Living  trees  were  attacked  in  June  of  this  year;  4  were  not 
attacked  in  June,  but  were  infested  in  October.  Of  tbe  4  girdled  trees  the  2  that 
were  hack  girdled  and  the  1  tl  at  was  belt-girdled  were  infested  and  died,  while 
the  I  that  was  girdled  to  the  heartwood  died  without  the  aid  of  Dendroctonus. 
Two  trees  attacked  last  year  recovered  and  were  not  attacked  this.  Two  attacked 
last  year  died  this.     Eleven  trees  were  not  attacked. 

The  9  trees  that  were  dead  on  June  19  averaged  19.3  inches  in  diameter.  The  8 
ungirdled  trees  that  were  attacked  this  year  averaged  15.7  inches  in  diameter. 
The  :;  girdled  trees  that  died  averaged  16.7  inches  in  diameter.  The  13  trees  that 
were  not  attacked  averaged  14.2  inches  in  diameter. 

GrBOUP  HI. 

This  group  is  situated  on  the  "  tote'*  road,  near  the  brook  crossing  near  Wight's 
( 'amp. 

Trees  girdled  ■June   /.;. 

Tree  No.  16:  Diameter,  17  inches:  sound  roots,  and  healthy  crown.  June  19, 
two  I  )em;roctonus  galleries,  one  at  girdle,  the  other  l-.V  inches  long.  July  1 1 .  about 
a  dozen  Dendroctonus  galleries,  the  longest  ones  2  inches:  without  eggs  or  larvae; 
several  single  beetles  dead  in  short  galleries  and  embedded  in  the  pitch.  Septem- 
ber 1,  six  or  eight  new  galleries,  without  eggs  or  larva. 

Tree  No.  17:  Diameter.  15  inches:  hack-girdled  at  base  of  roots.  June  19,  not 
attacked.  July  11,  one  Dendroctonus  gallery  with  eggs.  September  1.  one  gallery 
without  larva\     O  tober  4,  no  additional  attack:  tree  stiU  living. 

Tree  No.  18:  Diameter,  17  inches;  sound  roots,  and  large  crown;  an  infested 
tr<  e  20  feet  away.  June  19,  lightly  infested  by  Dendroctonus;  galleries  about  1 
inch  long:  had  entered  at  girdle  and  elsewhere;  also  some  Xyloterus  in  girdle  and 
elsewhere.  July  11.  thoroughly  infested  by  Dendroctonus:  galleries  '4  inches  long; 
Polygraphia  (?)  also  in  bark.  September  1.  thickly  infested  with  Dendroctonus, 
mainly  in  the  pupa  stage:  Xyloterus  in  wood:  sapwood  brown  and  blue;  leaves 
falling.  October  4.  recently  developed  adults  and  numerous  Xyloterus:  leaves 
half  fallen. 

A  19-inch  tree,  the  same  distance  from  the  infested  trees,  as  well  as  others  40  feet 
away,  were  not  attacked. 

Tree  No.  L9:  Diameter.  17  inches:  sound  roots  and  full  top.  June  19,  not 
attacked.  .Inly  11,  abundantly  infested  by  Dendroctonus:  Xyloterus  in  gir- 
dle. October  1.  large  larva',  pupae,  and  partly  and  fully  developed  adults  of 
Dendroctonus. 

I'll.'  above  trees  were  all  -it  the  time  of  girdling  within  a  few  rods  of  infested 
■ 

Tree  No.  80:  Diameter.  L5  inches;  standing  in  group  of  trees  killed  last  summer; 
-aiii.l.  .Inly  li  infested  with  Dendroctonus:  some  galleries  4A  inches  long, 
B,  but  none  hatched.  September  1.  abundantly  infested  with  Den- 
droctonus, pupa?,  and  lame  Larvee.    October  i.  Large  larva1  to  light-colored  beetles. 

July  li.  two  other  trees  in  suae  bunch,  not  girdled,  were  found  to  bo  attacked. 
I  am  not  certain  that  they  were  killed,  hut  think  that  they  were  not.' 


37 

Trees  girdled  July  11. 

Tree  No.  35:  Diameter.  15  inches:  50  feet  from  infested  trees.  September  1. 
two  Dendroctorms  galleries,  but  without  larvae  no  Xyloterus.  October  4.  same 
condition. 

Tree  No.  36:  Diameter.  15  inches.  September  1.  lightly  infested  by  Dendrocto- 
nus.  with  small  larva-.  October  4.  thickly  infested,  bark  drying  all  around:  larva11 
ha.f  grown. 

Tree  No.  37:  Diameter.  18  inches:  30  yards  from  infested  tree.  September  1, 
thoroughly  infested  by  Dendroctonus :  half-grown  Larvae;  leaves  beginning  to  fall. 
October  4.  medium  and  large  larra?  abundant:  bark  dying:  leaves  partly  fallen. 

Tree  girdled  Sept*  mber  1. 

Tree  No.  40:  Near  No.  37.     October  4.  not  attacked. 

Aside  from  the  trees  mentioned  above,  girdled  and  engirdled,  no  other  trees 
were  attacked  in  the  immediate  vicinity  of  this  ..roup:  therefore,  it  would  appear 
that  the  girdled  trees  had  exerted  considerable  influence  in  attracting  the  beetles. 

Group  IV. 

This  group  of  trees  is  situated  on  the  trail  north  of  Wight's  Camp. 

Trees  girdled  July  11. 

Tree  No.  31:  Diameter.  Is  inches:  away  from  infested  trees.  October  4.  not 
attacked  by  any  insec  t. 

T:ee  No.  32:  Diameter.  17  inches:  near  No.  31.  October  4.  three  Dendroctonus 
galleries  about  3  inches  long:  one  at  the  girdle. 

Tree  No.  33:  Diameter.  20  inches:  standing  with  trees  girdled  last  year:  no  liv- 
ng  beetles  found  in  the  bark.  September  1  and  October  4,  not  attacked  even  by 
Xyloterus. 

Tree  No.  34:  Diameter.  17  inches:  away  from  infested  trees.  September  1  and 
October  4.  not  attacked. 

Trees  girdled  September  l. 

Tre^  No.  41:  Diameter.  13  inches  standing  among  dead  and  infested  trees 
October  4,  no  evidence  of  attack:  mold  in  the  girdle. 

Tree  No.  42:  Diameter.  14  inches.     Octob  r  4.  not  attacked. 

Group  V. 

This  group  stands  near  the  outlet  of  Big  Island  Pond  at  the  head  of  Kennebago 
River,  where  much  infested  timber  was  observed  on  date  of  girdling. 

Tn  <  s  girdled  June  16. 

Tree  No.  21:  Diameter.  16  inches:  standing  among  infested  trees.  July  28,  a 
few  Xyloterus  entering  at  girdle,  but  no  Dendroctonus.  August  11.  same  condi- 
tion. 

Tree  No.  22:  Diameter.  1*5  inches:  near  infested  trees,  .luly  20,  one  Dendrocto- 
nu:  and  a  smaller  species  at  girdle.  August  1 1 .  two  Dendroctonus.  with  larvae  in 
bark  below  girdle. 

Tree  No.  23:  Diameter.  17  inches:  with  hollow  base  but  externally  sound  roots: 
close  to  infested  trees.     July  2G  and  August  11.  not  attacked. 

On  July  26  no  recent  infestations  were  observed  in  this  locality,  although  many 
badly-infested  trees  were  observed  here  on  June  16,  in  which  Professor  Ilopkins 
found  a  far  greater  number  of  parasites  and  predaceous  beetles  than  had  been 
found  in  any  other  locality.  On  August  11  a  group  of  three  infested  trees  was 
found,  which  was  probably  overlooked  in  July.     One  of  them  was  iniested  by 


38 

Dendroctonus,  Polygraphus,  and  Xyloterus;  another  showed  numerous  Dendroc- 
tonus galleries,  and  the  third,  a  12-inch  tree  with  decayed  roots,  had  numerous 
Dendroctonna  bm  rowa  reaching  to  the  wood,  but  not  completed.  Near  these  trees 
two  others  were  observed  that  had  each  a  decayed  root,  but  were  not  attacked; 
another  14-inch  tree,  attacked  in  1899,  had  recovered  and  was  not  attacked  this 
another  one,  20  Inches  in  diameter,  with  the  bark  dead  on  one  side  half  around 
the  trunk,  was  not  attacked.  Still  another  tree,  with  a  long  split  or  fissure  in  one 
side  had  been  attacked  last  year  and  died  on  one  side,  but  the  other  side  was  no 
attacked  this  year.  ( )ne  of  two  large  living  trees  standing  by  the  side  of  one  that 
died  !a>t  year  had  two  full  length  Dendroctonus  galleries  in  the  bark,  but  no  larva'. 
<  in.'  Tetropinm  pnpa  case  was  observed  in  the  sapwood. 

Stumps  of  trees  , -nt  last  year  within  10  rods  showed  no  evidence  of  attack  1  v 
Dendroctonna,  although  Xyloterus  (pnpse  and  immature  adults)  and  small  ba  k 
beetles  were  common. 

Group  VI. 

This  group  is  at  Hamel's  ( 'amp,  on  the  line  of  5  R.  5  and  5  R.  4,  within  a  mile 
of  the  New  Hampshire  line. 

ZVeea  girdled  June  <:. 

Tree  No.  8:  Diameter,  IS  inches:  heartwood  decaying;  external  wound;  one  root 
decayed;  loo  yards  from  infested  tree.  October  9,  tree  broken  off:  bark  dry;  leaves 
all  fallen;  Polygraph  us  abundant  in  bark,  but  no  Dendroctonus. 

Tree  No.  9:  Diameter.  1 7  inches:  thrifty,  with  sound  roots:  50  yards  from  infested 
trees.  October  9,  infested  with  Dendroctonus,  pnpse  and  adults,  also  Polygraphia 
and  Xyloterus:  leaves  fallen:  wrood  drying  and  staining. 

Tree  No.  10:  Diameter,  14  inches:  full  crown  and  thrifty:  HO  yards  from  infesied 
trees.  October  9,  infested  with  some  Dendroctonus;  more  Polygraphus:  also 
Xyloterus  and  a  few  Tetropium;  leaves  fallen  and  wood  dying. 

Tree  No.  11:  Diameter,  IS  inches:  close  to  infested  tree:  full  crown:  unsound 
roots;  probably  the  lower  portion  of  the  trunk  hollow.  October  9,  fallen:  prob- 
ably blown  over  about  September  1:  not  attacked  by  insects. 

Tree  No.  12:  Diameter,  17  inches:  sound  roots  and  full  crown:  dead  and  infested 
tie.  s  near  by.  October 9,  infested  with  Dendroctonus:  galleries  abundant:  adults 
occur  in  small  numbers:  wood  attacked  by  Xyloterus:  bark  dry  and  leaves  fallen. 

Tree  No.  13:  Diameter,  19  inches:  heavy  (Town  and  sound  roots;  '2  rods  from 
inft  sted  tree.  October  9,  infested  with  numerous  Dendroctonus:  1  roods  developed 
to  adults;  Polygraphus  and  Tetropium  in  bark,  and  Xyloterus  in  wood. 

Tre  '  No.  11:  Diameter,  b)  inches:  standing  among  others  of  the  same  size  and 
larger:  all  thrifty;  :*rods  to  infested  trees.  October  9,  infested  with  Dendroctonus: 
fuliy  developed  broods:  also  infested  with  Polygraphus  and  Xyloterus:  leaves 
fallen:  wood  dry. 

Tree  No.  15;  Diameter.  1(>  inches:  lull  crown  and  sound  roots:  standing  close  to 
infested  trees.  October  9,  infested  by  fully  developed  broods  of  Dendroctonus: 
wood  drying,  but  the  majority  of  the  leave-  holding  on. 

Peek  d  in  es. 

About  . I  one  90  a  considerable  number  of  trees  were  peeled  5  feet  up  from  base 
1)>  the  loggers  here.  <  >ne  whs  hack  girdled  for  peeling,  but  was  not  peeled.  This 
was  attacked  by  l  dendroctonus,  and  at  this  date.  (  tetol  er  9.  the  bark  is  full  of 
half-groWD  larva',  but  the  leaves  are  green.  Among  a  number  of  peeled  tries 
standing  near  girdled  tre.-,  Nos.  '.'  and  H)  one  has  a  few  1  dendroctonna  at  the  base; 
another  is  inf.  Bted  with  Polygraphna  in  large  numbers  and  the  leaves  are  falling: 
another  one  is  losing  its  leaves,  hut  appaientiy  net  infested:  still  others  are  yet 
hut  ahout  hall  of  them  have  a  number  of  Dendroctonus  galleries. 


39 

A  living  wind-felled  tree  here  was  not  attacked.  Near  Xo.  11  there  are  a  num- 
ber of  peeled  trees,  two  of  which  have  a  few  Dendroctonus  galleries  at  the  base. 
Several  have  Xyloterus  and  Tetropiuru.  l>ut  no  evidence  of  attack  has  been  noticed 
above  the  peeled  portion.  The  leaves  on  all  of  them  are  green,  but  some  are  begin- 
ning to  fade.  A  small  log  cut  near  by  and  left  is  full  of  Polygraphus,  but  contains 
no  Dendroctonns.  No  Dendroctonus  were  found  here  in  stumps  of  last  winter's 
cuttiug. 

Xotes  accompctnying  the  report. 

The  first  activity  of  Dendroctonus  was  noted  near  Wight's  on  June  10.  where  a 
tree  girdled  on  June  13  had  galleries  in  the  I  ark  as  much  as  1  _  inches  long,  with 
eggs.  Trees  girdled  on  May  29  and  others  had  galleries  2  inches  long.  At  other 
1  la  es  I  failed  to  nore  act  vity  of  the  insects  on  this  date,  except  four  or  five  bur- 
rows in  a  stump,  although  I  looked  for  it  carefully  n  infested  clumps  of  tro 

The  first  larvae  were  noticed  between  July  28  and  31  at  Big  Island  Pond.  They 
had  then  worked  about  an  inch  laterally  from  the  parent  galleries. 

On  July  11  the  trees  a"  Wight's  which  were  first  infested  had  galleries  as  much 
as  3  inches  long,  with  eggs,  but  no  larva?.  On  Sep  ember  1  the  same  trees 
showed  the  insert  mainly  in  the  pupa  form:  also  so  :e  large  larvte  and  recently 
developed  beetles.  On  October  4  the  broods  were  largely  in  the  full-colored  or 
matured  adult  form,  though  some  lag  ed  behind,  even  remaining  in  the  larval 
form.  A:  this  date  1  could  see  no  signs  of  any  of  the  beetles  emerging,  although  I 
looked  carefully. 

The  trees  girdled  in  June  and  July  indicate  the  time  required  for  the  develop- 
ment of  the  insect.  The  trees  girdled  on  September  1.  1  believe,  were  in  no  case 
attacked  by  insects. 

We  had  a  very  wet  June,  and  early  July  was  a:so  wet.  but  the  weather  was  dry 
in  late  summer.  On  September  1  the  leaves  had  not  commenced. to  turn,  but  by 
October  1  about  half  of  the  leaves  of  the  maples  had  fallen. 

In  my  identification  of  the  insects  I  was  not  always  certain  about  Tetropium 
and  Polygraphus. 

The  woodpeckers  that  work  on  infested  trees  are  probably  American  and 
Arctic  three-toed  woodpeckers.  There  may  be  others.  They  do  little  work  in 
the  summer. 

It  seems  that  any  exposure  of  t  e  wood— as  in  girdiing—  attracts  Xyloterus  and 
possibly  Dendroctonus. 

Trees  are  frequently  met  with  which  are  attacked  quite  abundantly  by  Den- 
droctonus. which  exc  .vate  galleries,  but  no  broods  develop.  Such  trees  fre- 
quently at  least — 1  think  generally— escape  attack  the  next  year. 

My  inference  as  to  the  attraction  exerted  by  g  rdled  trees  is  that  while  many 
beetles  are  attracted  to  them,  yet  the  attraction  is  not  great  or  from  a  long  dis- 
tance. The  evidence  furnished  by  Group  III  s  affirmative  on  this  point.  The 
results  with  Group  I[  are  inc  onclusive.  mainly  from  the  abun  \mce  of  the  beetles 
here,  but  also  Irom  exemption  of  tree  No.  T.  Tr.e  results  in  the  case  of  Group  I 
SH^m  to  show  that  distance  is  a  bar.  while  thos /  with  Group  II  further  indicate 
that  the  broods  migrate  only  a  short  distance."  The  evidence  furnished  by  trees 
Nos.  26,  27.  and  28  in  Group  I  is  affirmative,  but  the  surroundings  are  such  that 
the  test  is  inconclusive.  From  Groups  IV  and  V.  I  can  draw  no  striking  or  certain 
conclusions,  while  Group  VI  is  the  most  affirmative  of  all. 

As  to  windfalls.  I  can  only  state  from  general  impression  that  in  my  opinion 
they  are  not  specially  liab'e  to  attack  by  Dendroctonus.  and  that  the  same  is  the 
case  with  logs  left  in  yards,  tops  leit  in  woods,  etc. 

The  fact  that  6  of  the  0  trees  girdled  on  June  6  were  infested  and  killed,  while 
no  others  near  by  were  attacked,  is  strong  evidence  that  the  girdled  trees  attracted 
the  insects. 


40 


COMMENTS   ON    MR.    GARY'S   WORK. 

The  experimental  work  of  .Mr.  Gary  and  its  results  are  summarized 
in  the  following  table.  The  data  arc  arranged  in  the  numerical  order 
of  t  in-  i  ices  experimented  with. 

Sum  mart/  rinr  of  Mr.  (  'urifs  work. 


Number 
tree. 

In  what 

group. 

Diam 

eter  of 

tree. 

Dat.'  .,! 

girdling. 

Results  to  ( >ctober  4  to  9. 

1 11 1I11  s. 

I 

88 

May  39 

Not  attacked:  living. 

I 

]■> 

do    .,  . 

Not  attacked:  dying. 

i 

II 

:.'() 

.1..    ... 

Attacked:  dead:  leaves  fallen. 

II 

Hi 

do 

Do. 

•6  

ll 

i:> 

do.... 

Do. 

ll 

;£> 

.1.. 

Not  attacked:  dead;  leaves  fallen. 

8 

VI 

IS 

June  ti 

Not  attacked:  tree  blown  down. 

VI 

17 

do 

Attacked:  dead:  haves  fallen. 

VI 

U 

do 

Do. 

11    . 

VI 

IK 

do 

Not  attacked:  blown  down. 

•12   

VI 

17 

do 

Attacked;  dead;  leaves  fallen. 

•18  

VI 

111 

do 

Do. 

VI 

L3 

..  do  ... 

Do. 

VI 

hi 

do 

Attacked:  dying;  leaves  not  all  fallen. 

tl»i  

III 

17 

June  13 

Attacked:  living 

U7 

III 

I:, 

do 

Do. 

•18 

III 

i; 

do 

Attacked:  dead;  leaves  fallen. 

•19.. 

III 

17 

...do.... 

Attacked. 

';.'"  ..     .. 

III 

15 

do 

Do. 

:.'l  

V 

16 

June  hi 

Not  attacked:  living. 

V 

in 

..do.  .. 

Lightly  attacked:  living. 

z\ 

V 

17 

..  do  ... 

Not  attacked;  living. 

I 

13 

June  lit 

Do. 

25 

I 

is 

..do  ... 

Do. 

I 

80 

do    . 

Attacked:  dead. 

I 

IS 

do 

Do 

W 

I 

Hi 

do 

Not  attacked:  living. 

;;i 

IV 

IS 

July  11 

Do. 

m 

IV 

17 

..  do  ... 

Lightly  attacked:  living. 

38 

IV 

Mil 

...do  ... 

Not  attacked:  living. 

8*. 

IV 

17 

...do  ... 

Do. 

t86  

III 

15 

...do... 

Lightly  attacked:  living. 

+:&; 

III 

15 

...do... 

Attacked:  dying. 

•87  

III 

1H 

...do.... 

Attacked:  dying;  leaves  partly  fallen. 

Not  attacked:  living. 

in  

III 

IV 



Sept  l 

41    

115 

Do. 

IV 

II 

...do  ... 

Do. 

4:5 

II 

13 

...do.... 

Do. 

44 

II 

1:5 

...do.... 

Do. 

II 

.    13 

...do... 

Do. 

*  Trees  exerting  decided  attraction. 


I  Trees  lightlv  attacked. 


Of  the  four  trees  hack-girdled  and  one  tree  belt-girdled  on  May  29, 
two  hack-girdled  and  the  one  belt-girdled  were  attacked.  One  tree 
girdled  to  heartwood  was  not  attacked. 

Of  the  eighl  trees  hack-girdled  Oil  June  6,  six  were  attacked  and 
two,  having  diseased  wood  and  roots,  fell  without  being  attacked. 

Of  the  five  trees  girdled  on  June  13,  all  were  attacked. 

Of  the  three  trees  girdled  on  June  1(5,  two  were  not  attacked  and 
one  bul  lighl  ly. 

Of  the  five  trees  girdled  on  June  L9,  two  were  attacked  and  three 
were  not. 

or  the  seven  trees  girdled  on  July  ll,  two  were  attacked  seriously, 

two  lightly,  and  three  not  at  all. 

Of  the  six  trees  girdled  on  September  I,  none  were  attacked. 

of  the  fourteen  i  tees  girdled  on  June  6  and  13,  all  but  the  two  that 


41 

fell  were  attacked  by  large  numbers  of  Dendroctonus,  thereby  fur- 
nishing good  evidence  that  between  these  dates  was  the  proper  period 
(spring  of  1900)  to  girdle  the  trees  to  attract  the  insects. 

Of  the  twenty-five  trees  girdled  on  the  other  dates— May  29,  June 
19,  July  11,  and  September  1 — only  seven  were  attacked  by  sufficient 
numbers  to  kill  the  trees. 

rl  nese  results,  together  with  observations  by  the  author  during  the 
investigations  on  the  dates  of  the  appearance  of  the  leaves  and  flowers 
on  different  trees,  indicate  that  the  best  period  to  girdle  spruce  trees 
to  attract  the  spruce-destroying  beetle  away  from  other  trees  may 
vary  with  the  seasons,  hut  will  be  about  ten  days,  commencing 
when  the  catkins  (flower  stems)  are  falling  from  the  birches,  and  con- 
tinuing while  the  fire  cherry  and  the  hobble  bush  are  in  flower. 
Another  good  guide  will  be  to  commence  when  the  first  pupa-  of  the 
destructive  beetle  commence  to  appear  in  the  bark  and  continue  until 
the  beetles  commence  to  fly. 

SUGGESTIONS  AND  RECOMMENDATIONS. 

The  prime  objects  of  the  investigation  were  not  only  to  determine 
facts  relating  to  the  causes  of  the  death  of  the  spruce,  but  to  obtain 
evidence  on  which  to  base  suggestions  and  recommendations  for 
mitigating  or  controlling  the  ravages  of  the  spruce-destroying  beetle; 
preventing  the  total  loss  of  the  vast  amount  of  timber  already  killed, 
and  for  reducing  or  pre  venting  the  losses  from  its  ravages  in  the 
future. 

It  has  seemed  a  hopeless  undertaking  to  determine  practical 
methods  of  combating  invasions  of  destructive  insects  in  a  vast 
wilderness  of  virgin  forest,  or  to  accomplish  much  toward  prevent- 
ing total  loss  of  the  millions  of  feet  of  timber  killed  or  injured  by 
them,  especially  in  a  country  like  ours,  where  improved  forestry  is  in 
its  infancy.  But  with  a  knowledge  of  the  principal  depredator,  its 
habits,  its  life  history,  its  enemies,  and  the  conditions,  favorable  or 
unfavorable,  for  its  destructive  work,  facts  have  been  determined  on 
which  to  base  conclusions  relating  to  simple,  inexpensive,  and  prac- 
tical methods  of  combating  the  insects  and  preventing  a  large  part  of 
the  losses. 

It  then  rests  with  the  owner  of  the  property  to  study  the  practical 
features  of  the  problem  and  the  facts  determined  by  the  investigator, 
in  order  that  he  may  intelligently  apply  the  recommendations  to  the 
varying  needs  and  conditions  a*  in  each  case  seems  most  advisable. 
It  should  be  remembered  that  it  is  the  investigator's  mission  to  deter- 
mine the  facts  and  evidences,  and  present  them  with  recommenda- 
tions and  suggestions,  while  the  owner  of  the  damaged  or  threatened 
property  must  study  and  utilize  or  discard  them,  as  his  practi- 
cal judgment  and  business  interests  may  indicate  is  best  in  each 
particular  case. 


V2 

Millions   OF    REDUCING    THE    NUMBER   <)V    BEETLES. 

The  fact  1  hat  h  Large  number  of  beet  lea  must  attack  a  living,  heall  hy 
tier  in  order  to  inflict  injury  sufficient  fco  cause  its  death,  and  lluis 
offer  the  best  conditions  for  its  future  multiplication  and  spread,  is 
of  special  importance  since,  if  their  numbers  can  be  reduced  below 
that  necessary  to  kill  the  trees,  their  depredations  on  the  living  tim- 
ber  must  cud.  The  insect  can  then  onlysurvive  in  weakened,  dying, 
or  felled  trees.  Ii  would  thus  remain  harmless  until  some  specially 
favorable  condition  would  enable  it  to  accumulate,  or  migrate  from  a 
distance,  in  sufficient  numbers  to  again  successfully  invade  the  living 
t  imbe.r. 

The  facts  which  have  been  determined  regarding  the  habits  and  life 
history  of  the  beetle  suggest  three  methods  by  which  their  numbers 

can  he  reduced  : 

I.  To  regulate  i lie  winter  logging  operat  ions  so  1  hat  as  many  of  t he 
dying  and  infested  trees  as  possible  can  be  cut  and  the  logs  therefrom 
placed  in. rivers,  ponds,  or  lakes  between  October  1  and  Juno  1. 

Different  stages  of  the  Dendroctonus  remain  in  the  bark  during  the 
summer,  cease  active  work  about  the  middle  of  October,  remain  in  the 
bark  over  winter  and  until  about  the  middle  of  June  before  the  adults 
emerge.  The  part  of  the  trees  that  is  infested  is  that  which  is  util- 
ized for  logs.  Therefore,  if  the  trees  are  cut  anytime  after  they 
become  thoronghlj7  infested,  and  the  logs  are  hauled  to  the  landings 
in  the  winter,  placed  in  the  water  and  driven  out  of  the  woods  in  the 
spring,  vast  numbers  of  the  insects  will  be  either  drowned  or  so  far 
removed  from  the  larger  standing  spruce  thai  they  can  do  no  harm. 
There  are  eighl  months  in  which  to  do  the  work;  so  if  the  regular 
logging  operations  are  (as  suggested  by  Mr.  Cary)turned  in  thedirec- 
tion  of  the  worst  infested  areas  there  will  be  little  additional  expense 
in  the  practical  application  of  this  method. 

II.  To  regulate  the  summer  operations  so  thai  as  many  of  the 
infested  trees  as  possible  can  be  cut  while  the  bark  will  peel,  by  the 
removal  of  which  from  tin'  logs  and  stumps  of  such  trees  most  of  the 
insects  will  be  dest  roved. 

It  is  the  practice  in  some  sections  to  cut  the  spruce  at  a  time  when 
the  bark  can  be  readily  removed,  thus  facilitating  transportation  to 
the  mills;  therefore,  if  the  cutting  can  be  turned  in  the  direction  of 
the  dying  and  infested  spruce,  there  will  be  little  or  no  additional 
expense  in  cutting  and  removing  the  bark  from  such  trees,  and  thus 
allot  the  eggs  and  young  stages  of  the  beetle  will  be  effectually 
destroyed  by  the  exposure  and  the  drying  of  the  bark.  Another 
advantage  of  this  method,  it  would  seem,  lies  in  the  fact  that  trees 
peeled  either  in  ihe  winter  or  summer  can,  if  necessary,  be  left  in  the 
woods  for  several  years,  probably  without  serious  detriment.  The 
preservation  of  such  peeled  logs  could  be  facilitated  bjr  placing  some 
of  th<-  removed   bark  along  the  lops  of  the  logs  to  prevent   undue 


43 

checking  and  give  some  protection  from  the  elements.  Such  logs 
could  then  be  taken  out  when  reached  in  the  regular  cutting  and  log- 
ging operations. 

III.  To  girdle  healthy  trees  in  June  to  attract  the  beetles  away  from 
timber  that  it  is  desired  to  protect,  the  girdled  trees  to  be  cut  and 
peeled,  or  placed  in  the  water,  in  the  ordinary  practice  of  logging, 
previous  to  the  first  of  the  following  June. 

The  use  of  girdled  trap  trees  has  the  advantage  of  not  only  facili- 
tating the  destruction  of  the  insects,  but  of  attracting  them  away  from 
the  matured  timber  that  it  is  desired  to  leave  standing  for  future  cut- 
ting. Still  another  advantage  lies  in  the  fact  that  trees  may  usually 
be  selected  for  this  purpose  which  in  the  regular  logging  operations 
could  be  cut  and  hauled  to  the  streams  within  the  limited  time 
required.  The  beetles  which  are  attracted  to  the  trees  in  this  manner 
may  be  disposed  of  by  either  of  the  preceding  methods  mentioned,  so 
thai  the  only  additional  expense  over  the  regular  logging  operations 
would  be  the  cost  of  girdling. 

The  infested  spruce  which  can  not  be  reached  by  the  extension  or 
adjustment  of  the  summer  and  winter  logging  operations  might  be 
felled  and  the  bark  removed  from  the  infested  portions  of  the  trunks 
any  time  between  the  first  of  August  and  the  first  of  the  following 
June.  The  young  stages  of  the  insects  and  most  of  the  adults  would 
thus  be  destroyed  by  the  drying  of  the  bark  in  summer,  or  by  freezing 
if  removed  in  the  winter. 

Another  method  would  be  to  fell  and  "score"  (by  cutting  through 
tin1  bark)  the  top  of  the  infested  portion  of  the  felled  trunks  or  logs 
to  let  in  the  water,  which,  it  is  believed,  would  thus  produce  an 
unnatural  condition  which  would  kill  most  of  the  insects.  Experi- 
ments are  suggested  to  test  the  effects  of  water  absorbed  by  the 
impeded  logs  whether  left  in  the  woods  or  placed  in  the  water.  The 
adoption  of  this  method  is  not  recommended,  however,  until  experi- 
ment's prove  its  value  and  the  conditions  are  found  to  be  favorable  for 
its  practical  application. 

When  the  timber  is  dying  rapidly  in  a  given  area  of  greater  or  less 
extent,  and  the  trouble  is  perceptibly  spreading,  and  upon  examina- 
tion it  is  found  that  there  are  comparatively  few  insect  enemies  of  the 
beetle,  either  or  all  of  the  three  methods  should,  under  favorable  con- 
ditions for  their  practical  adoption,  prove  of  great  service  in  prevent- 
ing the  undue  multiplication  of  the  pest  and  protecting  the  living- 
timber  from  attack. 

If  the  trouble  seems  to  be  on  the  decrease,  and  upon  examination  it 
is  found  that  a  large  number  of  natural  enemies  are  operating  on  dif- 
ferent stages  of  the  spruce  beetle,  it  may  not  be  necessary  to  take 
active  measures  for  reducing  their  numbers.  Indeed,  under  specially 
favorable  conditions  for  the  enemies  to  operate,  it  may  be  best  to  do 
nothing,  for  under  such   conditions  an  attempt  to  destroy  the  enemy 


44 

of  the  spmoe  would   result   in  destroying  the  natural  enemies  of  the 

>| hi n« •  Imm'1  le  also. 

This  is,  however,  a  problem  requiring  considerable  knowledge  of  the 
Bubject.  Indeed,  ii  is  difficult  even  for  one  having  such  knowledge 
to  determine  whether  or  n<>i  it  is  best  to  leave  the  mallei-  to  be  taken 
care  of  l>\  friendly  insects  and  conditions.  Under  ordinary  conditions 
it  w  ill  probably  be  as  \\  < *  1 1  to  adopt  by  way  of  precaution  oik4  or  more 
of  the  simple  met  hods  suggested. 

While  ii  may  not  be  best  in  some  cases  to  cut  and  remove  the 
Infested  tiers  when  beneficial  insects  abound,  the  reverse  is  the  case 
when  applied  to  the  beneficial  woodpeckers. 

If,  as  has  been  made  clear  by  the  abundant  evidence  found,  the  birds 
destroy  a  Large  percentage  of  the  spruce-destroying  beetles  in  thou- 
sands of  infested  trees  during  a  single  winter,  it  is  plain  that  if  these 
birds  had  to  confine  their  work  to  a  half  or  a  quarter  as  many  trees,  very 
lew  of  the  insects  would  escape.  For  every  infested  tree  taken  out 
of  the  woods  through  the  adoption  of  either  of  the  three  methods  sug- 
gested, that  many  less  will  remain  for  the  birds  to  work  on  and  con- 
sequently fewer  beetles  would  escape  to  invade  the  living  trees. 

Previous  observations  by  the  writer,  and  a  study  of  the  problem  of 
the  relation  of  birds  to  injurious  and  beneficial  insects,  led  him  to 
believe  that  in  the  end  far  less  service  was  rendered  by  the  birds  t  han 
was  generally  credited  to  them.  This  was  believed  to  be  the  case 
mainly  on  account  of  the  failure  of  the  bird  to  show  any  decided  pref- 
erence  for  the  injurious  over  the  beneficial  insects.  In  the  case  of  the 
woodpeckers  of  the  Maine  woods,  which  feed  on  the  spruce-destroying 
beet  le,  however,  the  writer  is  convinced  that,  while  the  birds  may.  and 
doubtless  do.  destroy  many  insect  enemies  of  the  Dendroctonus,  they 
do  far  greater  good  than  harm.  It  would  seem,  however,  that  the 
relation  of  the  birds  to  the  beneficial  insects  of  the  northern  spruce 
forests  presents  some  novel  features  which  either  do  not  exist  or  have 
not  been  noted  in  other  sections  of  the  country. 

The  adults  and  larvae  of  the  common  Clerid  beetles  are  among  the 
most  efficient  insect  destroyers  of  bark  beetles.  In  ot  her  sect  ions  t  he 
larva-  of  these  friendly  insects,  as  a  rule,  after  they  have  attained 
their  lull  growth,  go  into  the  outer  bark  to  undergo  their  transforma- 
tions and  to  pass  the  winter.  Here  they  are  in  especial  danger  of 
destruction  by  the  woodpeckers.  It  appears,  however,  that  in  the 
northern  spruce  woods  they  have  learned,  possibly  through  the  sur- 
\  val  of  the  fittest,  or  the  per  pet  nation  of  an  acquired  habit,  to  escape 
the  birds  by  going  into  the  central  tubes  or  tunnels  in  the  main  gal- 
leries made  by  the  spruee  beetles  to  const  I'uct  their  pupa  eases  and 
Undergo  their  transformations. 

It  is  also  probable  thai  the  habit  of  the  principal  parasite  of  the 
spruce  beetle,  Which  makes  its  cocoons  in  the  inner  bark,  may  enable 
it  to  escape  the  birds.      The  fact,  also,  that  these  parasites  must    have 


45 

thin  bark  through  which  to  insert  their  ovipositors  and  reaeli  the 
Dendroctonus  larvae  when  depositing  eggs  suggests  that  this  class  of 
beneficial  insects  may  be  favored  in  their  work  by  the  removal  of  the 
outer  thick  bark  by  the  bird.  Thus  the  parasite  would  be  able  to 
kill  many  of  the  beetle  larvae  that  escape  the  birds. 

If  the  sprnce-destroying  beetle  should  become  rare,  through  the 
efforts  of  the  lumbermen  and  the  work  of  birds  and  other  natural 
enemies,  the  lumbermen  might  repay  the  birds  for  their  great  services 
by  providing  food  for  them.  This  could  easily  be  done  by  girdling  to 
the  heartwood  numbers  of  spruce  trees  in  June  and  leaving  them 
stand  until  the  following  spring.  These  would  be  infested  by  numer- 
ous other  bark  beetles,  like  Polygraphias,  which  breed  in  the  cuttings 
and  are  readily  attracted  to  injured  trees.  Flat-headed  and  round- 
headed  bark-mining  grubs  would  also  be  attracted  to  and  breed  in 
such  trees  and  would  furnish  food  for  the  birds.  The  trees  could  be 
cut  in  the  spring  following,  so  that  there  would  be  no  loss  and  possibly 
much  gain. 

The  owners  of  the  spruce  of  the  Northeast  owe  a  lasting  debt  of 
gratitude  to  these  friendly  birds,  and  should  exert  every  possible 
effort  to  protect  them  and  increase  their  numbers  so  that  their  good 
work  may  continue. 

UTILIZATION    OF   DEAD    SPRUCE. 

While  this  is  an  economic  problem  for  the  consideration  of  the 
expert  practical  forester,  it  may  not  be  out  of  place  for  the  writer  to 

contribute  the  results  of  his  observations,  which,  if  not  authoritative 
on  such  a  question,  may  at  least  be  suggestive. 

The  observations  of  the  writer  led  him  to  believe  at  the  time  the 
investigations  were  being  made  that  a  considerable  quantity  of  the 
dead  limber  which  had  been  dead  five  to  fifteen  years  or  more 
(PL  XIV)  had  yet  considerable  value,  especially  as  pulp  wood.  He 
was  all  the  more  convinced  of  this  after  a  recent  visit  to  the  spruce 
areas  in  West  Virginia,  where  it  was  found  that  just  such  dead  stand- 
ing and  felled  spruce  as  was  observed  in  Maine  was  here  furnishing 
a  Large  amount  of  sound  pulp  wood.  Upon  examination  of  this  wood 
in  the  yard  and  in  the  trees  before  and  after  they  were  felled  it  was 
found  that  some  of  the  trees  from  which  considerable  good  material 
was  secured  had  been  dead  at  least  twenty  years.  Nearly  all  were 
known  to  have  been  dead  at  least  seven  years,  and  this  in  a  section 
where  previous  investigations  indicated  that  the  wood  decays  more 
rapidly  than  elsewhere. 

The  advantages  of  utilizing  the  wood  of  dead  timber  for  pulp  over 
that  for  ordinary  lumber  is  in  the  fact  that  it  can  be  cut  into  short 
lengths,  the  good  taken  and  the  bad  left  in  the  woods.  The  profitable 
utilization  of  such  material  depends,  of  course,  upon  the  cost  of  get- 
ting it  out  of  the  woods,  as  well  as  convenient  and  moderately  cheap 


46 

transportation  to  the  factories,  hi  the  mountains  of  West  Virginia 
this  problem  is  solved  by  broad  and  narrow  gauge  railroads,  with 
branch  bramroads  running  through  the  forest,  the  latter  extending 
into  and  following  up  i  he  cuttings.  Therefore  1 1 » < *  cost  of  taking  out 
the  dead  along  \\  ith  the  Living  timber  is  a  small  item. 

The  determination  of  the  relative  value  of  the  dead  timber  and  its 
rate  of  deterioration  under  differenl  conditions  and  in  different  Locali- 
ties, together  with  recommendations  for  the  practical  utilization  of 
thai  which  is  worth  saving,  is  a  problem  which  will  doubtless  receive 
its  due  share  of  attention  from  Mr.  Caryand  other  experl  foresters  in 
northwestern  .Maine.  Mr.  Cary  is  in  an  ideal  position  for  the  future 
investigation  of  such  matters.  The  knowledge  recently  gained  by 
him  from  being  with  Dr.  Von  Schrenk  in  his  investigation  of  fungous 
diseases  of  trees,  ami  the  writer,  in  the  investigation  of  the  insect 
enemies,  will  probably  render  the  results  of  his  further  investigations 
all  the  more  valuable. 

It  is  plain  that,  if  as  Large  a  percentage  of  the  wood  of  the  dead  1  ices 
remains  sound  for  as  long  a  period  as  our  observations  would  indi- 
cate, the  amount  to  be  saved  in  i1s  utilization  at  as  early  a  date  as 
possible  would  go  Tar  toward  paying  the  expenses  of  extending  roads 
for  the  purpose  far  in  advance  of  the  regular  cutting. 

IMPORTANCE    OP    HARVESTING    THB    MATURED    CROP   OF   SFRUCK. 

Since  ii  has  been  definitely  determined  that  the  spruce-destroying 
beetle  confines  its  attack  to  spruce  trees  over  10  inches  in  diameter, 
and  that  by  far  the  Larger  percentage  killed  by  it  range  from  18  to 24 
inches,  it  seems  clear  thai  the  matured  or  Large  timber  should  be  har- 
vested as  rapidly  as  is  consistent  with  good  business  management. 
This  would  not  only  save  the  Larger  Living  trees  from  attack,  but 
would  facilitate  the  utilization  of  such  of  the  dead  trees  as  may  yet 
yield  a  quantity  <>f  merchantable  material. 

This  is  a  problem,  however,  like  the  preceding,  which  must  be  con- 
sidered from  the  standpoint  of  the  experl  forester,  and,  in  its  applica- 
tion, made  to  conserve  the  best  interests  of  the  timber  owners.  It  lias, 
therefore,  been  the  writer's  intent  ion  to  do  no  more  than  to  call  atten- 
tion to  what  has  been  Learned  of  the  relation  of  the  spruce-destroying 
beetle  t«>  the  virgin  spruce  areas  and  matured  timber  as  an  important 
factor  to  be  considered  in  future  management. 

Mi.  Cary  refers  to  the  subject  of  cutting  the  spruce  in  damaged 
and  endangered   localities  in  The  Forester,   March,  L900,  page  54,  as 

follow  » : 

Tli.  re  need   not    be.  under  preeenl   conditions,  any  comparatively  great  loss. 

Lumbering   is   being  carried  on  throughout  the  region  iii  which  the 

■    is  known   to  exist.     The  bodies  of   uncut  timber  are  nearly  all  accessible. 

e  turned  in  the  direction  of  the  damaged  or  endangered  localities. 

and  cutting  serves  not  merely  to  Bare  the  dead  timber  to  us,  but  also,  it  would 


47 

appear,  to  carry  away  much  of  the  source  of  infection.  The  bunchy  way  in 
which  the  dead  timber  stands  is  also  in  our  favor.  Evidently  the  normal  flight 
of  the  beetle  is  short,  for  the  dead  trees,  as  a  rule,  stand  in  groups:  those  killed 
one.  two.  or  three  years  ago.  together  with  the  insect  colony  working  perhaps  in 
green  t  mber  close  beside  them.  This  trouble,  indeed,  may  also  he  regarded,  in 
one  way.  as  a  benefit  to  our  forests.  So  far  as  it  may  determine  a  policy  of  thin- 
ning rather  than  stripping  the  land,  it  will  exert  a  favorable  action  which  will 
never  be  entirely  lost  on  the  reproduction  of  spruce. 

SUMMARY. 

The  results  of  the  investigation  and  review  of  literature  relating  to 
the  unhealthy  condition  of  the  spruce  in  the  Northeast  may  be  sum- 
marized as  follows: 

Extensive  dying  of  spruce  from  New  York  to  New  Brunswick  has 
occurred  at  various  times  and  periods  from  about  1818  to  1900. 

Within  this  period  spruce  to  the  amount  of  many  billions  of  feet 
has  died,  and  much  of  it  has  been  a  total  loss. 

The  cause  of  the  death  of  a  greater  part  of  this  spruce  lias  been 
the  depredations  of  insects. 

The  primary  depredator  in  the  forests  investigated  is  a  bark-mining 
beetle,  the  spruce-destroying  beetle,  Dendroctonus piceaperdaj  n.  sp. 

Vigorous  trees,  to  all  appearances  in  perfect  health,  are  attacked 
and  killed  by  this  beetle. 

The  largest  trees  and  best  stands  of  timber  suffer  most  from  its 
ravages. 

It  passes  the  fall,  winter,  and  spring  in  all  stages  from  young  to 
matured  larva-,  and  immature  to  matured  and  old  adults,  in  the  bark 
of  trees  attacked  by  it  in  the  summer. 

Activity  commences  early  in  June:  the  beetles  commence  to  emerge 
from  their  winter  quarters  about  the  middle  of  June,  and  continue 
to  come  out  probably  until  about  the  1st  of  September. 

In  the  latitude  and  altitude  of  northwestern  .Maine  there  is  but 
one  brood  of  the  insect  each  year  from  the  first  parent  beetles  that 
emerge  in  June,  while  those  that  emerge  later  in  the  summer  do  not 
develop  broods  of  adults  until  the  next  summer. 

The  broods  of  the  beetle  do  not  remain  in  a  dying  or  dead  tree 
more  than  one  year  after  it  commences  to  die.  The  estimated  num- 
ber of  adults  which,  under  favorable  conditions,  may  emerge  from 
an  average-sized  tree  is  from  five  to  seven  thousand. 

It  is  estimated  that  an  average  of  three  pairs  of  beetles  to  the 
square  foot  of  bark  on  10  to  15  feet  of  the  trunk  of  an  average-sized 
tree  are  sufficient  to  kill  it.  and  that  0.000  beetles  breeding  in  one 
tree  may  be  sufficient  to  kill  from  :?(•  to  25  more  trees. 

The  principal  insects  that  aid  the  primary  enemy  in  killing  the 
-  after  the  first  attack  has  been  made  are  (1)  a  smaller  bark 
beetle  (Polygraphus  rufrpennis)  and  (2)  a  round-headed  bark  and 
wood  miner  (Tetropium  oinriamo-pterurn). 


4S 

There  are  main  oilier  bark-mining  beetles  and  bark  and  wood- 
mining  grubs  which  may  aid  the  primary  enemy  in  killing  the  trees 
and  in  the  subsequent  destruction  of  the  wood. 

The  principal  enemy  of  the  spruce-destroying  beetle  and  other 
bark-infesting  enemies  of  the  spruce  consists  of  the  woodpeckers, 
which  destroy,  it  is  believed,  from  50  to  75  per  cent  of  the  broods  of 
the  spruce  beetle  in  many  hundreds  of  trees  each  year. 

Two  other  enemies  of  the  beetle  are  of  special  service  in  reducing 

their    numbers,    8    small    wasp-like    parasitic    insect   (BrOCOTl   simplex) 

and  an  ant-like  predaceous  beetle  ( Thanasirmus  nubilus  Kl.?). 

The  principal  methods  recommended  inthisreporl  for  preventing 
Losses  from  the  ravages  of  tin1  beetle  maybe  briefly  summarized  as 

follow  8  : 

I.  Regulating  the  winter  cutting  so  as  to  include  as  many  of  the' 
infested,  dying,  and  dead  trees  as  possible,  and  placing  the  logs  from 
the  same  in  the  water  before  the  1st  of  .lime. 

II.  Regulating  the  summer  cutting  so  that  as  many  recently 
attacked  trees  as  possible  may  be  cut  and  t lie  bark  removed  from 
their  i  ranks  and  st umps. 

III.  Girdling,  early  in  June,  a  Large  number  of  trees,  where  Logging 
operat  ions  will,  or  can,  be  carried  on  1  he  following  summer  and  winter, 
in  the  vicinity  of  infested  localities,  the  girdled  trees  to  be  felled 
and  the  logs  containing  the  broods  of  the  insect  attracted  to  them 
either  peeled  or  placed  in  the  water  before  the  first  of  the  succeeding 
June. 

The  results  of  one  season's  experiment  in  girdling  trees  indicate 
thai  the  besl  time  to  girdle  spruce  for  this  purpose  is  when  the  flow- 
ers (catkins)  are  falling  from  the  birch,  and  while  the  fire  or  bird 
cherry  and  the  hobble  bush  are  in  bloom.  The  girdled  trees  should 
be  sound  and  healthy,  and  not  less  than  L5  inches  in  diameter. 

The  besl  method  of  girdling  seems  to  be  thai  of  hacking  through 
the  bark  with  an  a\  into  the  sapwood  and  around  the  trunk  2  or  3 
feci  above  the  base. 

Suggestions   for   utilizing  the  dead  and  matured   Living  spruce  to 

prevent   loss  arc  as  follows: 

A  Large  percentage  of  the  dead  spruce  appears  to  remain  sound  and 
valuable  forpulpwood  for  a  longer  period  than  has  heretofore  been 
recognized. 

The  matured  Living  timber  should  be  cut  and  utilized  as  rapidly  as 
possible  to  prevent   insect  attack. 


EXPLANATION  OF  PLATES. 


3506 — No.  28—(il 4 


PLATE  I. 
Tlie  apructiS  of  Maine. 

Spruce,  dead  and  living  trees  at  yamekee.  er's  camp. 
i  .  Whit*-  Spruce,  near  Wight's  camp. 
i  .  Black  Spruce,  on  trail  to  Lower  Black  Pond 
d,  In  dense  spruc<  woods. 
50 


Bui.  28.  New  Senes.  Div.  jf  Enl  : 


Plate  I. 


The  Spruces  of  Maine. 


PLATE  II. 
Dendroctonws piceaperda  Hopk.  n.  sp. 

1,  Adult,  dorsal  view. 

2,  Adult,  lateral  view:  <(,  Prothorax,  anterior  view;    b,  tip  of  elytron,  showing 

arrangements  of  stria1,  and  interspaces  ;   9  ,  last  abdominal  segment  of  female, 
dorsal  view;    J  .  last  abdominal  segment  of  male. 

3.  Pupa:  a,  Profile  of  head  and  prothorax. 

4.  Larva:  <i,  Dorsal  plates  on  last  abdominal  segment;  />.  foot  scars  (?)  on  ventral 

surface  <>f  thoracic  segments;  c,  profile  of  ventral  thoracic  lobe  showing  foot 
scar  (?). 
52 


I 


Bui.  28,  New  Series,  Div.  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  II 


Dendroctonus  piceaperda  Hopk.,  n.  sp. 


PLATE  III. 

Gallrrics  ami  mine*  of  tlif  fspruce-destroying  beetle  (Dendroctonus pieeaperda 

Hopk.  n.  sp. ) 

Primary  and  secondary  galleries  or  mines  of  the  spruce-destroying  beetle,  .show- 
ing parts  of  six  primary  galleries — reduced  about  one-fourth. 


Bui.  28,  New  Series,  Div.  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  III. 


Galleries  and  Mines  of  the  Spruce-destroying  Beetle. 
I  Dendroctonus  piceaperda,  Hopk.l 


PLATE  IV. 
Galleries  and  mines  of  Dendroetonus  pieeaperda  in  spruce. 

Primary  and  secondary  galleries  or  mines  of  the  spruce-destroying  beetle. 
56 


Bu  .  28,  New  Series,  Div.  of  Entomoiogy,  U.  S.  Deo:    of  Ag 


Plate  IV. 


Galleries  and  Mines  of  Dendroctonus  piceaperda  in  Spruce 


PLATE  V. 
old  galleries  of  Dendroctonus  piceaperda  in  spruce. 

a.  Grooves  <>n  the  surface  of  the  wood  of  a  tree  that  had  been  dead  about  twelve 

years. 
l>.  Wounds,  or  incomplete  galleries. in  bark  of  living  tree:  wound  tilled  with  pitch. 
C,  From  dead  tree. 

d,  From  living  tree,  in  which  some  of  the  wounds  were  healing. 
«  .  From  old  dead  tree,  the  sap  wood  of  which  was  decaying. 
58 


\T...   Series    C   •    :;E--:~:  ag|    U.  S.  Dept.  of  Agriculture. 


Plate  V. 


J..* 


/ 


■ 


W 


Old  Galleries  of  Dendroctonus  piceaperda  in  Spruce. 


PLATE  VI. 
Spruce  hark  tilicnoing  growth  of  fungus,  Polyporu*  volvatim. 

A  fungus.  Polyporus  volvatus  Peck,  growing  from  holes  made  in  the  bark  of  trees 
killed  by  the  spruce  beetle — natural  size. 
60 


_  -    New   Sei  rs    Div.  of  Entomology.  U.  S.  Deot.  cc  Agriculture 


Plate  VI. 


^^m«»«r  _wugw>  yV»  »» .  —  ■s^h  H^^B^H 

wj 

IN 

lyjv^s  <i 

CTmEwl 

*SKBEES|l^iSr  1 

•2? 

IpKH^m^ 

i 

Wufifc  ■■'■     ^% 

i^^^^^^^^^EMKT^-  _    i    fs^B^H      H^Bki.5 r-  !8^»  &.T91 

fgc 

Spruce  Bark  showing  Growth  of  Fungus.  Polyporus  volvatus. 


PLATE  VIII. 
Work  of  secondary  and  other  enemies  of  the  spruce. 

a.  Work  of  Tomicus  picea  Hopk.  MS.  in  white  spruce  bark. 

I.  Work  of  PityopMhorus  cariniceps  Lee.  in  spruce  hark  and  grooving  the  outer 

wood. 
«.  (Galleries  of  the  destructive  pine-lark  beetle  (Dendroctonus  frontalis)  in  pine 

I 'ark:  also  attacks  spruce. 
./.  Work  of  Dryocwtes  pic*  a  Hopk.  MS   on  the  surface  of  spruce  wood, 
i .  Galleries  of  the  spruce  Polygraphus  on  surface  of  x>ieces  of  spruce  driftwood. 

found  in  Parmacbeene  Lake. 
04 


-    New  Se- e;    D  •    of  Entomology,  U.  S.  Deot.  o' Agriculture. 


Plate  VIII, 


!i 

1tc 

t 

!     — 

aTt- 

f 


Work  of  Secondary  and  other  Enemies  of  Spruce. 


3506— No.  28—01 5 


65 


PLATE  IX. 
QaUeriex  of  Pol  mint  pints  rufipennis  showing  different  stages. 

<f.  I>.  c,  Freshly  excavated  galleries  in  living  bark. 
d  <  )ld  galleries  in  dead  bark. 
66 


Bu     28,  New  Series,  Div.  of  Entomology,  U.  S.  Dept.  of  Agr  : 


Plate  IX. 


1 


Galleries  of  Polygraphia  rufipennis.  showing  different  Stages. 


PLATE  X. 
Mines  of  Tetropium  cinnamopterum. 

Surface  of  the  wood  of  a  "peeled"'  and  felled  spruce,  showing  mines  made  by  thl 
spruce  Tetropium— natural  size. 

9 


Jul.  28,  New  Series,  Div.  of  Entomo:ogy    U.  S.  Deot  of  Agncultu-e. 


Plate  X. 


Mines  of  Tetropium  cinnamopterum. 


PLATE  XL 
Work  of  Xyloterua  bivittatun,  and  Phloeotribus  picea  iopk.  MS. 

a.  Work  of.  the  wood-mining    beetle,  Xyloterus  bivittatus,  in  the  sapwood  of 

spruce — natural  size. 

b.  Fungus  (Polyporus  volvatus)  growing  from  mines  of  Xyloterus  bivittatus  on 

the  surface  of  the  wood  after  the  bark  had  been  removed — natural  size. 

c.  Work  of  Phlceotribus picea  Hopk.  MS.  in  spruce. 

70 


Bui.  28    New  Series.  Div.  of  Entomology.  U.  S.  Deot.  of  Agriculture. 


Plate  XI. 


Work  of  Xyloterus  bivittatus  and  Phlceotribus 

PICEA   HOPK.    M.  S. 


PLATE  XII. 
Work  of  Dendroctonu8  frontalis  and  Dendroctonus  terebrans. 

I  From  drawings  illustrating  Bulletin  5t>,  W.  Va.  Aarr.  Exp.  Station.) 

a.  Dendroctonus  frontalis :  A,  adult;  7>,  pupa;  C,  larva;  D,  adult  of  Dendrocto- 
nus ten  brans;  E,  larva. 

/»,  Dendroctonus  frontalis:  J,  tibia:  B,  tarsus;  C,  D,  E,  antennae;  E,  G,  mouth 
parts.  Dendroctonus  terebrans:  H.  tibia:  I,  tarsus:  J,  K,  L,  31,  X,  antenna — 
all  enlarged. 

c.  Pitch  tube  made  by  Dendroctonus  frontalis — natural  size. 

d.  Healing  wounds,  from  living  pine  tree,  made  by  D.  frontalis— reduced. 

e.  Pupa  cases  of  D.  frontalis  in  outer  pine  bark. 

/.  Dendroctonus  frontalis:  A.  B,  longitudinal  section  of  primary  galleries:  C, 
egg  in  egg  cavity  inside  of  gallery — the  latter  enlarged:  others  reduced. 

</,  Healing  wounds  in  living  tree:  E,  Dendroctonus  frontalis;  E,  Dendroctonus 
t<  rebrans. 

A,  Work  of  Dendroctonus  frontalis  in  pine  bark  is  shown  at  .4.  C,  D,  E,  E.  G; 
work  of  P.  terebrans  in  pine  bark  at  B,  II.  I:  larva  at  work  at  II. 

Note. — Both  D,  frontalis  and  I>.  terebrans  attack  spruce, 
72 


Bui.  28,  Ne*  S=r.es,  D.v.  of  Enio-  :   Jg)     -     S    Dep:.  of  Agi 


Plate  XII. 


L  X'    i 


$ 

» 

T 
r 

1 

■^■fEij 

Work  of  Dendroctonus  frontalis  and  Dendroctonus  terebrans. 


PLATE   XIII. 

Top  of  Black  Sprue*    infested  icith  a  caterpillar  and  a  plant-louse.    This  shows 
characteristic  appearance  of  the  top  and  cones  of  the  Black  Spruce. 
74 


Bui.  28.  New  Series,  Dv.  o<  Er-omology,  U.  S.  Dept.  of  Ag- 


Plate  XIII. 


Top  of  Black  Spruce  infested  with  a  Caterpillar  and  a  Plant  Louse. 


PLATE   XIV. 
Dead  spruce;  also  fir  and  birch. 

a.    Old  dead  spruce  and  a  dead  birch  in  cutting. 
bl.  Remains  of  very  old  dead  spruce. 

W .  Appearance  of  spruce  tree  after  it  has  been  dead  five  to  ten  years  or  more 
C,    White  Spruce  near  gamekeeper's  camp,  dead  three  or  four  years. 
il.    Dead  spruce,  fir.  and  birch,  killed  by  fire, 
c.    Dead  spruce  and  fir  on  summit  of  Rump  Mountain. 
76 


I  •   E    -  ■  |       -     5.  Deo:      -'-;-;,--- 


P.ATE    XiV. 


Ob 


\ 


1,            f  \  * 

1   *       1                        I  i 

i      fl  f 

III                                               11 

II                1       1  If  • 

; 

7 

f?    ■PP- 

• 

Dead  Spruce:  also  Fir  and  Birch. 


PLATE   XIV. 
Dead  spruce;  also  fir  and  birch. 

a,    Old  dead  spruce  and  a  dead  lurch  in  cutting. 
bl.  Remains  of  very  old  dead  spruce. 

b:.  Appearance  of  spruce  tree  after  it  has  been  dead  five  to  ten  years  or  more 
C,    White  Spruce  near  gamekeeper's  camp,  dead  three  or  four  years. 
(/.    Dead  spruce,  fir.  and  birch,  killed  by  fire. 
e,    Dead  spruce  and  fir  on  summit  of  Rump  Mountain. 
76 


Bu     28     '.r   ■   Sei  es    -   ..  :;  n-:oTioiogy,  U.  S.  De;>t.  of  Agriculture. 


Plate  X!V. 


Ob 


\ 


I 


Dead  Spruce;  also  Fir  and  Birch. 


PLATE  XV. 
Timber  flooded  and  killed  by  toater  on  the  Magallotcay. 

ii  At  Camp  in  the  Meadows. 
b.c  Between  the  dam  and  the  camp, 
c  Also  showing  the  bog1  spruce  growing  in  the  water. 

7- 


Bui.  28.  New  Series,  D^v.  of  Entomology,  U.  S.  Dept.  of  Ag-  : 


Plate  XV. 


Timber  flooded  and  killed  by  Water  on  the  Magalloway. 


PLATE  XVI. 

Sections  of  wood  cut  from  Balsam  Fir,  showing  rapid  growth  after  the  old  spruces 

die  or  arc  felled. 

1.  From  fir  by  dead  tree  in  cutting  of  about  1888. 

2.  From  fir  standing  by  dead  spruce  in  old  cutting  of  about  1886. 

3.  From  fir  standing  by  dead  tree  that  showed  the  work  of  the  spruce  beetle.   Tree 

evidently  died  about  1888. 

4.  From  fir  in  blow  down  of  about  1871,  which  was  followed  by  another  in  about 

1885-86. 

5.  From  fir  in  blow  down  of  about  1886. 

6.  From  spruce  standing  by  large  tree  broken  by  a  storm  about  1886.     Evidence 

was  found  in  this  tree  that  it  was  living  when  felled  and  that  it  had  been 
attacked  after  falling  by  the  spruce  beetle.  Both  galleries  and  remains  of 
beetles  were  found  in  the  bark. 

7.  Section  of  small  suppressed  spruce  about  45  or  50  years  old — all  natural  size. 

80 


o 


B'j  .  28,  Ne/v  Se:  43.  D  v.  of  Entomology,  U.  S.  Dept  of  Agr  : . 


Plate  XVI. 


^^-^ 


c 


Sections  of  Wood  cut  from  Balsam  Fir,  showing  rapid  Growth  after 
the  old  Spruces  die  or  are  felled. 


PLATE  XVI. 


Sections  of  inxxl  cut  from  Balsam  Fir,  showing  rapid  growth  after  the  old  sj)ruces 

die  or  are  felled. 


3. 


4. 


Tree 


From  fir  by  dead  tree  in  cutting  of  about  1888. 

From  fir  standing  by  dead  spruce  in  old  cutting  of  about  1886. 

From  fir  standing  by  dead  tree  that  showed  the  work  of  the  spruce  beetle. 

evidently  died  about  1888. 
From  fir  in  blow  down  of  about  1871,  which  was  followed  by  another  in  about 

1885-86. 
o.  From  fir  in  blow  down  of  about  1886. 

6.  From  spruce  standing  by  large  tree  broken  by  a  storm  about  1886.     Evidence 

was  found  in  this  tree  that  it  was  living  when  felled  and  that  it  had  been 
attacked  after  falling  by  the  spruce  beetle.  Both  galleries  and  remains  of 
beetles  were  found  in  the  bark. 

7.  Section  of  small  suppressed  spruce  about  45  or  50  years  old — all  natural  size. 


o 


Bu  .  28,  New  Ser  es,  Div.  of  Entomology,  U.  S.  Dept  of  Agr  culture 


Plate  XVI. 


Sections  of  Wood  cut  from  Balsam  Fir,  showing  rapid  Growth  after 
the  old  Spruces  die  or  are  felled. 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  4564 


